Twenty established varieties collected from all over India were tried in RBD with four replications. A wide range of variation was found in respect of all the characters. But the magnitude of phenotypic variation does not reveal the relative amounts of genetic variation. Hence genetic coefficient of variation was worked out. According to this, the number of seeds per plant showed a large amount of genetic variability compared with the number of branches and 100 seed weight. Heritability estimates worked out in the broad sense has shown that all the characters, except the number of branches per plant had highest heritability values and 100 seed weight, especially, had the highest heritability values. Similarly, high genetic advance was noticed for the weight of seeds, number of pods and number of seeds per plant. Whereas, the genetic gain in respect of the number of branches and 100 seed weight was comparatively low in spite of the latter character having high heritability values. From this, it is clear that number of pods and number of seeds per plant showed high heritability and greater genetic advance, which means that these two characters are governed largely by additive effects.
Genetic correlation coefficients in general were greater than the phenotypic and environmental coefficients among all the characters. This indicates that though there is a strong association between various characters, the phenotypic expression is influenced by the environment. Number of seeds, number of pods, number of branches and 100 seed weight was positively correlated with the yield/plant. The phenotypic and genetic correlation between the number of seeds and the number of pods/plant with yield were highly significant, which means that yield is largely a function of these characters. The genetic correlation of branches with yield was high and significant, which indicated the importance of this character, though indirectly, in influencing the yield. The genetic association between the number of branches and the number of pods and seeds per plant was quite high and positive, which reflected that the number of branches is a valuable index for effective selection towards higher yield.
Hundred seed weight was negatively correlated with the number of seeds and pods per plant as may be expected from the fact that more pods or seeds per plant would tend to reduce the size of the seeds. However, this character contributed towards total yield and that the correlation though poor was positive.
Thirty six different types obtained from Jabalpur, Indore, Raipur, Sehore and Gwaliar in Madhyapradesh. An experiment was laid out on a simple randomized design with 5 replications. Of the thirty six lines, Indore Choudi and CRS-No.32 had bushy habit. Others were stem twiners. Variation in pod colour were light-green, green, dark-green and purple.
- Early types (65-90 days): Pusa early, Bunch, Jabalpur-2 Sehore –1, Sarguja-1 and Indore Makanbalore.
- Medium types (90-116 days): Jabalpur-15, 10,18,13,17,5,14, 3, 1, Indore Choudy, Indore Red Seed, Indore-1, Sehore-4, 3, 2, Sarguja-2, Rewa, Raipur, GWAR-1& 2.
- Late types (115-140 days): CBS No. 32, Indore-3, 2, Jabalpur- 16, 6 and 11.
There were three different shapes of pods: flat, curved, and cylindrical. Pods of 16 lines had blunt end and the rest with pointed end. The pod size varied significantly. Jabalpur –9.14, 15, 16, 18, Rewa, Sehore –4 and Gwaliar–1, 2 was rated as the best in respect of pod size.
Number of pods/plant differed significantly. Indore Choudy, Jabalpur 5 and 3 were better in respect of this character, while Jabalpur –17 was most inferior. Sehore –4, Sarguja – 2 and Gwaliar –1 were intermediate.
There was significant variation in seed number/pod which varied from 3. 52 to 5. 23 seeds/pod in Indore Choudy and Sarguja–2, respectively. Jabalpur–2, 11, Indore-2, Gwalier-1, CBS No.32 and Sarguja –4 were found good for seed number / pod.
Average weight of 100 seeds of the types was significantly different. Jabalpur –14, 11, 3 and 9 and Gwaliar –2 were the best. Indore Choudy, CBS No.32 and Indore Red Seed were most inferior.
A significant difference was found in respect of average yield/plant. Jabalpur –14 gave maximum yield and Jabalpur –17 yielded the lowest. The types from Jabalpur were better yielders than the others.
Protein content varied from 19.42 % to 25.11 % in Jabalpur–5 and Rewa, respectively. The narrow range of variation in protein content has been obtained in different types.
He reported that yield per plant, pod number and plant height had high genotypic coefficient of variation in 196 selections of field bean and he revealed high heritability for pod yield and pod number depicting additive gene action for these characters
An experiment was conducted in 1972 with 36 varieties of Dolichos lablab. Each type was planted in a single row with 4 replications. Observations were made on 12 characters.
Yield was positively and significantly correlated with leaflet area (0.4324), days to flowering (0.5038) and 100 seed weight (0.5132). Similar significant correlations were observed to a lesser extent between yield and pod width (0.3166) and protein content (0.3938). However, only highly significant negative correlation was observed in pod length with yield (–0.4575). Significant positive correlation was noted between 100 seed weight and petiole length (0.3368); but the former had negative correlation with pod length (–0.3928). The negative correlation between pod length and yield was because pod length had negative correlation with pods/plant (–0.1249).
The positive correlation of leaflet area with yield indicates the importance of the assimilatory surface in productivity. The positive association of yield with flowering duration established the fact that early varieties are low yielders and vice versa.
In petiole length, a negative direct effect (–0.0321) but a positive correlation, has further confirmed the importance of other characters in effecting correlation with yield. Again, correlation was greater than the absolute magnitude of effect indicating the importance of complementary effect of other characters. The 100-seed weight was mainly responsible for this behaviour. The correlation between these two characters was positive and significant, whereas a negative direct effect of petiole length was also affected by an indirect effect via leaflet area.
The direct effect of leaflet area was stronger and thus reflected in the positive correlation with yield (0.4324). The same was true for days to first flowering (0.3104), 100-seed weight (0.3050) and seed: pod ratio (0.1359).
The positive correlation of leaflet area, 100-seed weight and protein with yield indicated their importance in increasing yield. The path-coefficient analysis confirmed the findings of correlation studies, as the direct effects tend to increase their positive effects. Besides, both these characters were complementary since their indirect effects on each other tended to favour the direct effects. Hence the inclusion of these characters in a selection programme for high yielding lines might pay rich dividends. Pod number was an important character. However, petiole length and pods/ plant were not useful indices for selection in this crop.
The phenotypic coefficient of variation (PCV) was higher than genotypic coefficient of variation (GCV) for all the characters studied. This shows high degree of environmental influence in determining the phenotype.
High heritability and high genetic gain were observed for number of pods per plant, seed yield per plant, weight of pods and length of inflorescence. But days to flower, days to maturity, seed protein, etc. had high heritability but low genetic advance. From this, it could be inferred that, if heritability was due to additive gene effects, it would be associated with high genetic advance and if it is due to non-additive gene effects, it would be associated with low genetic advance.
In general, the genotypic correlations were higher than phenotypic correlations in most of the characters. Thus the correlation studies showed that there is ample scope for the improvement of yield by selecting a genotype having higher pod number and pod weight since seed yield and pod weight are highly correlated.
Nine field bean genotypes were subjected to genetic analysis of 14 quantitative characters through a complete diallele technique and association analysis in order to investigate the nature of inter- relationships among these characters.
A large genotypic coefficient of variation was observed for the characters pod yield per plant, pods per plant, seed yield per plant, inflorescence length, pods per inflorescence and plant height. High heritability (broad sense) and genetic advance was also observed for pod and seed yields and pods per plant. At both levels, inflorescence and pods per plant showed high positive and significant correlations with pod and seed yield/ plant, which in turn showed significant correlations among themselves. Among the six characters taken for path coefficient analysis, pods per plant showed highest direct effect on seed yield per plant at both genotypic and phenotypic levels, next being inflorescences per plant.
An experiment was conducted with 18 varieties in RBD with 3 replications during kharif 1982. Observations were recorded on days to first flowering, days to first picking, number of flowers per cluster, number of pods/cluster, 100-seed weight, pod length, pod width and green pod yield/plant. Genotypic and phenotypic coefficients of variation, heritability and genetic advance values and correlation coefficients were worked out.
Significant variation was found for yield and all other characters under test. Strains FD-1 and JDL-77 were found the earliest and the latest, respectively. Number of flowers per cluster ranged from 10.73 to 22.87. The maximum number of flowers were recorded with the variety FD-8 followed by 7010 and FD-5 and the minimum with JDL-85. Maximum number of pods per cluster was with FD-8 and the minimum was with JDL-3. Seed weight varied from 25.07 to 49.95 g in FD-1 and HD-60, respectively. Genotypes 6802, JDL-71, FD-5 and HD-66 were found desirable.
Significant differences were found with regard to green pod yield per plant. Selection 7010 gave maximum yield per plant followed by HD-60, JDL-85 and JDL-37, whereas FD-1 was the lowest yielding.
The coefficient of genetic variation was the lowest (15.10) for days to first picking and highest for pod width (36.5%) and green pod yield/plant (30.67%). Chances were low for the improvement for the days to first picking as GCV was low. All the characters had high heritability values, days to first picking showed highest heritability value (96.58) and the lowest were for length of pod (30.09).
High heritability for days to flowering was not associated with high genetic gain, indicating less scope for improvement through selection for this character. But in the case of pod width and number of pods/cluster, both heritability values and genetic gain were high. This suggests the operation of additive gene effects for these traits.
The green pod yield/plant showed significant and positive correlation with pod width and 100-seed weight. Obviously, selection for these two traits can be effective for the improvement in pod yield. Highly significant and positive correlations were found for days to first flowering with days to first picking, number of flowers per cluster with number of pods/cluster, 100-seed weight with pod width. Significant and positive correlation was also found between number of pods and pod length. It is, therefore, possible to combine them in a selection index for making selection of all of them simultaneously.
Das, indicated that 100-sed weight and green pod yield/plant had heritability of 91.4 and 85.6% respectively. Seedling height was positively correlated with length and breadth of first leaves. Path analysis showed direct negative effects for all characters studies on green pod yield. Selection for large first-leaf breadth was suggested for the development of a high yielding plant type.
In this study, segregation for petiole colour, stem colour, photoperiodic sensitivity and spreading plant habit was studied in F2 of the cross CO.7 x Adilabad of garden bean. The purple colour in petiole was governed by tow complementary genes Pp1 and Pp2 while that of stem by three complementary genes viz., Ps1, Ps2 and Ps3. The spreading plant habit (Sg) and photoperiod sensitivity (Se) were controlled separately by one dominant in each case. The genes Sg and Se were linked with crossover value of 7.82% per cent while Sg and Pp1 were linked with COV of 32.92%. The gene Se was linked with Pp1 with COV of 63.16%. Further the gene Pp2 was associated with either Ps1 or Ps2 or Ps3 with COV of 1.36 or 6.14%.
Significant differences were found for all the characters, which suggest that there is a good range of variability among genotypes. Maximum yield and pods per plant were recorded in two lines while two others showed highest pod weight, length and width of pod. One line was found to be the earliest to flower, having maximum number of branches and minimum vine length, pod weight, length and width of pod among all the lines.
Maximum range of variation was found with pod yield per plant. The minimum range of variation was exhibited by pod width. The phenotypic coefficient of variation for all the characters was found to be more than genotypic coefficient of variation, which indicates considerable influence of environment on the expression of characters.
The characters like pod yield/plant, pods/plant and pod weight showed high coefficient of variation in both the years. This suggests greater scope for effective improvement.
Broad sense heritability varied from 99.60 with pod yield/plant to 82.52 with branches/plant. The genetic advance as per cent of mean was high for number of pods and pod yield. High heritability values associated with high genetic advance, if considered together are more useful than heritability alone. In this study, high heritability and high genetic advance were found for pod yield/plant, pods/plant, and weight of pod, pod width and number of branches per plant suggesting additive gene action. It is, therefore, possible that selection for these characters may be effective.
Das, (1990) obtained 92 accessions of D. lablab from Rahuri in Maharashtra in 1985 and grouped them into 3 different flowering type groups: early, medium and late. Genotypes in the late group were taller, had more leaves and a larger green fodder yield. Data are tabulated on the promising late flowering genotypes, IC 24654, IC 28823–1 and Black seeded, which had green fodder yields of 1322, 1440 and 1433 g/plant, respectively.
Breeding material comprising of 36 genotypes was tested in RBD with 3 replications during July, 1986 at Haryana Agricultural University,Hisar. Significant variation was found among the lines for all characters. At phenotypic level, a fairly strong and significant among eight characters was between yield and all other components, except pod length. In general, the magnitude of genotypic correlation was higher than the phenotypic correlations. Positive and significant association of height of plant, number of pods/ plant, weight per pod with yield suggested that effective improvement in pod yield through these components could be achieved.
The strong positive association (0.8215) with yield was only due to its direct contribution (0.8918), which was highest in magnitude, thereby indicating a true correlation and could be taken as a major component for the improvement of yield. It is concluded that making selection on the basis of pods per plant, plant height and pod weight have good chances towards improvement.
The green pods of hyacinth bean are used as vegetable, whereas mature seeds are consumed as pulse. Dry seeds are a rich source of proteins. Along with improvement of protein quantity and quality, restructuring the viny habit of the plant towards bushy, photo-insensitive types can bring about an improvement in yielding capacity and thus lablab bean becomes a major source of quality protein.
These varieties of Lablab niger Medik, viz., JDL-53, JDL-79 and K-6802 are indeterminate in growth habit and photo-sensitive. Whereas the variety Hebbal of Dolichos uniflorus Lam. is determinate and photo-insensitive. Thus Hebbal as a female parent was crossed with other three varieties in 1985-86 during August–March at Kalyani in West Bengal. F1 hybrid seeds thus obtained were grown during 1987-88 and 1988-89 to advance the generations to F2 and F3. Selections were made for determinate growth habit and photo–insensitivity. Determinate growth of the main vine and branches bearing terminal inflorescences produced typical dwarf statured plants with photo–insensitivity.
Seed coats were removed from the seeds and protein was extracted from defatted seed meal of each of the 40 lines by Lowry’s method. Sodium Dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) was done following Laemmli’s (1970) method where the defatted seed meal of each line was dissolved in 1.25. M Tris-Hcl (pH 6.8) containing 2% SDS and 5% 2–mercoptoethanol kept in refrigerated condition overnight, incubated in a boiling water bath for 2 minutes and centrifuged at 10,000 rpm. The supernatant was run in SDS-PAGE disc gel having 5% stacking gel and 12.5% resolving gel for one hour. Protein bands were stained by 0.25% coomasie blue.
Distance migrated by protein
Rf = ---------------------------------------------------------------
Distance migrated by Bromophenol blue tracking dye
Apparent molecular weights of the protein bands were determined by comparison with the standards, viz., thyroglobulin (Mr. 3,30,000) transferring (Mr.76, 000), ovalbumin (Mr.43,000) and myoglobin (Mr.17,200) obtained from Sigma Chemical Co. USA.
40 types showing best combination of dwarfness and photo–insensitivity were selected in F3 generation. Among these 40 isolates, 24 were from the cross JDL79 x Hebbal, 9 from K–6802 x Hebbal and 7 from JDL.53 x Hebbal crosses. Protein content varied appreciably among the parents and the lines selected from F3 generation of each cross. The protein content of the parents was comparatively low. Range of variation was high in lines derived from JDL79 x Hebbal cross. However, average protein content in lines of K 6802 x Hebbal was highest. These results indicate that there is a scope for further improvement of protein content of selected lines in subsequent generations.
Further selection in F4 and F5 generations with concurrent thrust on the plant characteristics and seed quality and seed protein quality and quantity will not only help to attain homogygosity of desired morphogenetic characters, but will also go a long way in stabilizing the altered protein patterns of improved lines. The dwarf stature and improved protein quantity and quality of lines will considerably ease the cultivation of Lablab niger as a dual purpose crop – green pod as vegetable and dry seeds as pulse – and also act as major source of vegetable protein.
One hundred and ninety six germplasm accessions from exotic and indigenous sources were in a lattice design with two replications. The characters chosen for study were length of internode, days to 50% flowering, number of spikes/plant, total length of spike, effective length of spike, pod set percentage, number of pods per spike, length and width of pod, days to maturity, plant height, plant spread, fodder yield/plant, number of productive pods/plant, pod yield/plant, number of beans/pod, 100 – bean weight and bean yield per plant.
Genetic constants were calculated by adopting standard procedures. Analysis of variance revealed highly significant differences for all the characters studied. Phenotypic and genotypic variances were very high for plant spread, number of pods/plant and pod yield/ plant. They were followed by fodder yield, number of productive pods per plant, bean yield per plant, days to maturity and also plant height. The other characters showed less variance. Except internodal length, days to maturity and days to 50% flowering, all other characters revealed wide differences between their phenotypic and genotypic variance. PCV was higher than GCV for all the characters. Moderate value of PCV and GCV were noticed for number of pods per spike, plant height and number of beans/pod.
Small differences between PCV and GCV indicate the less influence of G x E interaction which reflects on reliability of selection on the basis of phenotypic performance. Low PCV and GCV were observed for length of internode, length of pod, breadth of pod, days to 50% flowering, pod–set percentage, days to maturity and 100 bean weight. High heritability was observed for days to maturity, length of internode, days to 50% flowering, total length of spike, effective length of spike, length of pod, plant height, number of pods per plant, pod yield per plant and 100-bean weight.
Moderate heritability estimated were recorded for number of pods/spike, number of spikes/plant, breadth of pod, bean yield/plant, plant spread and pod–set percentage. However, low heritability values were noticed for number of beans/pod.
High heritability associated with high genetic gain were exhibited by pods/plant, pod yield/plant and number of productive pods per plant, which indicated the influence of additive gene effects in expression of these characters. Therefore, it must be worthwhile to exercise selection for these characters. High heritability for plant height, total length of spike, days to 59% flowering, effective length of spike, 100 bean weight, length of internode and length of pod were not associated with high genetic gain. This means that these characters may be controlled by non – additive gene effects.
Thirty genotypes collected from India and other countries were sown during 1984-85 in a RBD plot with three replications at Tamil Nadu Agricultural University, Coimbatore.
All the 30 genotypes studied for 13 characters showed maximum genotypic coefficient of variation for dry matter production followed by total leaf area. Heritability was highest for number of leaves, followed by plant height and dry matter production, whereas, it was moderate for crude protein, phosphorus, potassium and calcium contents. Genetic advance as percentage of mean was maximum for dry matter production. Significant correlation was observed in 22 character pairs. Green fodder yield showed positive and significant genotypic correlation with plant height, dry weight of leaf and stem and dry matter production. So far as successful breeding programme is concerned, the fodder characters such as dry matter production, number of leaves, and total leaf area offer much scope for further selection for improving the fodder yield of Lablab bean.
A total of 12 genotypes collected from different parts of the state were tried in experiment with RBD design with 3 replications during 1984.
Significant variation was observed among the genotypes for different characters involved in the study. High genotypic coefficient of variation in inflorescence length, pod weight, Vitamin C content, pod breadth, flowers per inflorescence, pod yield per plant and pod length indicated the existence of variability for selection based on these characters. High heritability and high genetic advance in inflorescences length, pod weight, pod breadth, Vitamin C content indicated the additive gene effects in their expression and direct selections can be made based on these traits for improvement. The effect of non-additive genes is evident in main stem length, days to flower bud emergence, flowers per plant and seeds per pod. Thus heterosis breeding is needed for these characters for improvement.
With a view to measure the variability among the genotypes for flower and pod characters, estimation of genetic parameters and for information on associations among the flower and pod characters with good yield, the study was undertaken.
All the characters under study exhibited high degree of variation among the genotypes. In most of the cases little difference between genotypic and phenotypic coefficient of variations was observed which indicated that environment had little influence. The highest GCV was found in green pod yield and number of green pods per plant. Moderately high GCV was observed in respect of individual pod weight, number of flowers and pods per inflorescence, number of inflorescences per plant and rate of pod abortion.
Heritability estimates (broad sense) were high for most of the characters and medium for the rate of flower abortion, while the rate of pod abortion and number of pods per inflorescence showed low estimates (32% and 55%, respectively).
The traits which have high heritability as well as high genetic gain are pod yield, number of pods and inflorescence per plant, pod weight and number of flowers per inflorescence. This indicates that these are the traits governed by few major genes or additive gene effects even if they are under polygenic control.
High heritability estimates with low genetic advance for rate of flower abortion suggested non-additive type of gene action and genotype x environment interaction play a significant role in the expression of this trait.
Number of flowers per inflorescence had a significant positive genotypic and phenotypic correlation with rate of flower abortion, number of pods per inflorescence number of green pods and inflorescences per plant had only significant positive genotypic correlation with rate of pod abortion, but significant negative correlation with individual pod weight. Significant positive genotypic and phenotypic correlations existed between number of pods per inflorescence and green pod production. But rate of pod abortion and number of inflorescence per plant showed only positive significant correlation and individual pod weight showed negative significant correlation with number of pods per inflorescence. Rate of pod abortion had significant positive correlation with number of green pods per plant at genotypic and phenotypic level. Number of inflorescences per plant had strong positive significant genotypic and phenotypic correlations with pod production. Significant positive genotypic and phenotypic correlations existed between pod weight and pod yield per plant and number of green pods and pod yield per plant.
This study suggested that important characters like number of pods and inflorescences per plant and individual pod weight had maximum contribution for increasing pod production. Selection programme based on these characters may lead to the improvement of pod yield in hyacinth bean.
Seven parental lines of Lablab purpureus viz. K-6802, JDL-79, Chakdah Local, JDL-17, H.D-18, JDL.-53, JDL-73 and one cultivar of Dolichos biflorus (Macrotyloma uniflorum), Hebbal Avare were used for this study. The genetic analysis of the said characters was done from 8 x 8 diallele set (without reciprocal). The genotypic coefficient of variation (GCV) as well as phenotypic coefficient of variation (PCV) were high for all the characters and the meager differences between GCV and PCV indicated the importance of the heritable component for their expression. High value GCV coupled with high heritability and high genetic gain indicated the scope of improvement in these characters through direct selection.
Seven cultivars of Lablab purpureus (K6802, JDI-79, Chakdah Local, JDL-17, HD-18, JDL-53 and JDL-73) and one cultivar of Dolichos biflorus (Macrotyloma uniflorum) (Hebbal) were used for genetic analysis and for the study of combining ability effects for some seed characters, viz., number of seeds per pod, seed weight per pod, single seed weight, seed length, seed width, seed thickness and seed yield per plant. Chakdah Local was the best general combiner for number of seeds per pod and seed yield per plant. Whereas JDL-73 x Hebbal, HD.18 x JDL-73 and HD-18 x JDL-53 were identified as potential specific combiners for seed yield per plant. The highest magnitude of heritability in the narrow sense was recorded for single seed weight; minimum heritability in the narrow sense was recorded for seed length and seed yield per plant. The estimates of genetic parameters indicated that most of the characters studied were controlled by additive gene variance.
An experiment was conducted at Pulses Research Station, Navsari, during 1995 – 96 to study the G x E interaction and stability performance in Indian bean Dolichos lablab. The G x E interactions was significant for all the traits except 100–seed weight. Among parents, NVS–141 was stable for seed yield/plant, while NVS 101 and NVS 62 were stable under unfavourable environments. The highest yielding hybrid, Red Paria x AKW 9304 was stable for seed yield in unfavourable environments. And the high yielding hybrids NVS 61 x NVS 102, 125 36 x NVS 121 and Red Paria x NVS 102 were identified as stable for seed yield per plant, specifically under good farming conditions.
In this study 107 Lablab bean germplasm were evaluated representing 20 different countries in Asia, Africa, South America and Europe for major morphological characters such as growth habit, plant type, number of branches, flowering response to photoperiod, pigmentation on on stem, petiole, leaf vein, leaf margin, petal, sepal, pod and seed coat and size of leaf, pod and seed. Variation was found among the germplasm (dissimilarity value ranged from 0.0 to 114.6) but no definite regional gene pool was identified. Wild type accessions were very close in their morphology, whereas Asian accessions showed much variation.
Country bean exhibits a great diversity in phenotypic traits, which include plant habit, stem surface, stem colour, leaf margin, leaf vein, nature of stipule, nature of petiole, bud colour, flower colour, pod colour, seed colour, seed mosaics, seed lustre, seed shape, seed size and seed weight. The phenotypic traits are important, but may be unreliable when positive identification of an accession is desired, owing to the scarcity of their variants, environmental plasticity, its dependence on the stage of development and intra–allelic interactions. Morphological markers provide limited data on patterns of domestication and evolution. Isozyme and protein markers are often subjected to developmental and environmental variations and may not be suitable for distinguishing closely related accessions owing to the low levels of polymorphism and limited number of loci.
The technological advancement of plant molecular techniques related to DNA based markers provides powerful and reliable tools for a variety of purposes including evaluation of variation with in a germplasm, tagging of genes for agronomically important traits and in genomic mapping. Most of the important characters are controlled by polygenes. The number of genes and their interactive effects controlling the expressions of desirable attributes in country bean are poorly understood.
An evalution from the agronomic and production point of view shows that there are promising genotypes with economic potential in yield, early flowering and maturity. Biochemical characters, nutritional value and tolerance or resistance to biotic and abiotic stresses. Unfortunately, information on these aspects supported by molecular marker– assisted analysis in country bean is lacking.
Mapping and sequencing of plant genomes would help to elucidate gene functions, regulation, and their expressions. Linkage analysis is one of the basis and indispensable methods in genetics. Linkage can define the genetic distances between polymorphic traits which may be recognized as differences in restriction fragment lengths or nucleotide sequences at an allelic locus. But such a map in country bean using molecular markers for identifying molecular linkages with quantitative and qualitative traits is lacking. The identification of such linkages will lead to a valuable breeding programme for the genetic improvement of country bean.
This study was carried out at the University of the North Experimental Farm at Syferkinl and at a small holder farmer field at Dalmada near Polokwane in the Limpopo Province during 2002–03 growing season. Thirty three accessions mainly from MA–types RB–8 and RB–3 plus 3 local types (cv. Rongai, selected for 3 different seed colours) were evaluated in a completely randomized block design with 3 replications. Protein and tannin contents in dry seeds of MA–type–8 were also analysed.
The results of the preliminary data indicate great diversity for flowering, maturity, and biomass accumulation and growth types. Most of the accessions were early flowering. Three local materials included in the evaluation remained vegetative even after 130 days. Hence, within the new accessions evaluated, there seem to be materials suitable for the typical rainfed conditions in the Limpopo Province.
Early flowering types accumulated less biomass compared to the late season types. Both biomass accumulation and also harvest index will be helpful in providing farmers with options to use Lablab in different circumstances such as a forage crop, grain legume, cover crop, rotational crop or as a component crop in an inter–cropping system. It is highly recommended that particular attention be given to foster country–specific or region–specific informal seed systems such as seed fairs in order to avoid dependence of small holders on commercial sources or even international imports. Thus with increasing research efforts, a better understanding can be gained of the variability pattern available in the crop.
Wide variability was present in the material for pods per plant, pod yield per plant, grain yield per plant. These characters also exhibited high heritability associated with high genetic advance indicating that the additive gene effects were operating for these characters. Significant and positive association of grain yield was observed with pod yield per plant, pods per plant, branches per plant, days to 50% flowering, days to maturity, plant height, and inflorescence per plant and 100-seed weight. Based on mean performance of 10 characters, genotypes GA-19, GA-97, GA-101, GA-20, GA-107 and GA-75 exhibited superiority for yield and other characters to checks and they could be preferred for further improvement in grain yield.
This study showed that Lablab purpureus L. var. typicus is widely cultivated in many of the states like Tamil Nadu, Karnataka, Andhrapradesh, Orissa, Madhyapradesh, Bihar, Jharkand, West Bengal and North-Eastern States. The plants of this group in general are indeterminate, photosensitive and vegetable poded with wide variation and diversity in pod shape and colour. An exploration was undertaken with the objective of collecting vegetable Dolichos (pole type) landraces and to understand the variability and distribution pattern in eight central districts of Tamil Nadu, viz., Dindigal, Madurai, Sivaganga, Pudukottai, Thiruvarur, Thanjavur, Tiruchrapalli, and Karur. Totally 97 pole type vegetable poded Dolichos landraces were collected from these eight districts. Maximum number of 22 collections (22.7%) were made in Thiruvarur district followed by Thanjavur–16 (16.5%) and Madurai district-15 (15.5%). In Dindugal and Tiruchirapalli districts there were 11 collections (11.33%) each and they were closely followed by Sivaganga (10 collections with 10,3%) and Karur district with 9 collections (9.3%). Among all the eight districts explored minimum number of landraces (three) was found in Pudukottai district with 3.1%. During collection, data were recorded on pod length, pod width, pod weight and pod colour. Pod length ranged from 6.5 to 18.3 cm and the maximum pod length was recorded in NM 0486. Similarly, pod width ranged from 1.0 to 4.0 cm with the maximum value in NM 049. The pod weight ranged from 40–180 g (NM 0413). Totally 9 different pod colours were observed. These were light– green, green, greenish–purple, purple–green, pink, deep–pink, purple, deep–purple and cream. Maximum of six different pod colours were observed in Madurai and Karur districts followed by Thanjavur and Tiruchirapalli (5 each). Thus, the study revealed that there is a wide variability and diversity for pod length, pod width, pod weight and pod colour among Dolichos accessions in the Central Districts of Tamil Nadu. The collections are further evaluated to isolate pole type vegetable lines.
In Indian bean, PCV values were slightly greater than GCV, revealing very little influence of environment for their expression. High heritability was expressed by days to first flower, number of pods per plant, pod length and pod yield per plant. High value of heritability along with high genetic advance was observed for number of pods per plant followed by days to first flower and days to first picking. Genetic advance as per cent of mean was observed maximum for number of pods per plant and pod yield per plant. Pod yield per plant showed positive and significant association with number of pods per plant and significant negative correlation with days to first flower and days to first picking at both genotypic and phenotypic levels. Path analysis revealed that number of pods per plant, number of days taken to first picking; pod length, pod width, seed width and seed length had direct positive effect on pod yield per plant. Multivariate hierarchical clustering depicted the classification of 46 Indian bean genotypes in 2 groups with 17 and 29 genotypes. First group further divided into 2 groups with 7 (VRSEM-765 is genetically different from 6 other genotypes) and 10 genotypes, while 29 genotypes divided into 2 clusters with 13 and 16 genotypes, respectively.
Correlation and path analysis studies were conducted using 32 genotypes of dolichos bean (Dolichos lablab L.). Correlation coefficient analysis revealed that pod length and marketable pod weight had the positive correlation with marketable green pod yield per plant. Hence, direct selection for these traits may lead to the development of high green pod yielding dolichos genotypes. Path analysis revealed that selection based on pod length and length of inflorescence could be the effective in developing high yielding genotypes of dolichos bean for Chhattisgarh plan.