Eighty-one genotypes of field bean comprising 32 exotic and 49 indigenous collections were subjected to canonical and multivariate analysis for twenty characters.
The Canonical variable analysis has shown that the first three vectors accounted for 71.34% of the total variability produced by all the 20 characters. Of these, three vectors, days to flower, days to maturity length of pods and seed protein contributed maximum towards divergence.
16 clusters were formulated based on D2 value calculated over 20 characters. The clustering pattern did not follow geographical distribution but was at random. It was observed that early and medium maturing genotypes had slightly higher percent of seed protein than the late maturing genotypes. These two groups could be clearly demarcated since they aggregated separately on two sides of the graph. As in Canonical variate analysis, discrimination was marked for days to flowering, days to maturity and seed protein. Great diversity existed among most important characters which might have resulted due to long term selection in different directions by natural and human forces.
In another experiment, the F2 and F3 generations of four intervarietal crosses: HA.3 x CB (cross A), HA.3 x US.8 (cross B), HA.1 x 208 and HA-1 x 169 (crosses C and D, respectively) were evaluated with the objective of assessing the variability, choosing the desirable cross and sibs within the selected cross, assessing the dependability of F3 performance over that of F2 and finally to understand the impact of genetic distance on the selection of parents for hybridization.
In the F2 generation, the crosses A, C and D exhibited high mean and variability for number of pods per plant, weight of pods and seed yield per plant.
The mean of the F3 was considerably reduced for all these characters. In the F3, the crosses A and C maintained their superiority over the other two crosses in their performance and variability, especially the most important yield contributing character, number of pods per plant.
In the F2, high heritability with high genetic gain was observed for number of pods per plant, number of inflorescences per plant, weight of pods and seed yield which revealed the usefulness of these characters in formulating selection indices. Number of pods per plant, weight of pods and seeds per pod exhibited strong correlation with seed yield per plant and between themselves as seen in the D2 experiment.
Transgressive segregation beyond the parental mean was observed in the F3 generation, which indicated that selection could be commenced in the F3 generation. A random ten percent of the F2 segregants were advanced to F3 generation. The results revealed the adequacy of this proportion of the selected plants for further evaluation .
The overall performance of all the four crosses revealed that maximum coefficient of variation with high mean values for three quantitative characters, namely, number of pods per plant, weight of pods and seed yield per plant were higher in cross A (HA.3 x CB) which had the maximum inter–cluster distance of 491.92. The number of transgressive segregation was also highest in this cross. Thus there appears to be an influence of genetic distance in the selection of parents with high coefficient of variation for important yield contributing traits in field bean.
Nayar reported that days to flower, days to maturity, and length of pods and seed protein content contributed maximum towards genetic divergence. He studies 81 genotypes those were grouped into 17 clusters. It was observed that early and medium maturing types possessed higher seed protein percentage. IC 3244 (UP) had the highest seed protein (31.59%) as against IC 10191 (Rajasthan) which contained 18.29%. The clustering pattern did not follow the geographical classification. Chikkaballapur and Hebbal Avare 3 which had maximum inter cluster distance resulted in maximum transgressive segregation on crossing.
Commonly grown varieties of Dolichos lablab in different agro climatic regions of the state (MP) along with some improved ones were tried in randomized block design with five replications at JNKVV, Jabalpur. Observations were made on 10 characters. Mahalanobis’ Statistics was used to measure the genetic divergence.
The genotypes formed 13 Clusters, six of which were single variety Clusters. Cluster IV included the largest number of varieties (13). Bold seeded varieties, Jabalpur-4, Jabalpur-3 and small seeded Indore Choudy and CBS No.32 formed independent Clusters mainly differing in 100-seed weight. The 100-seed weight being 50.28, 45. 48. 11.81 and 13.67 g, respectively. The genetic distance was found to be maximum (72.4) between groups VI (Jabalpur-10, Jablpur-11) and XIII (CBS-32) followed by single variety groups- Jabalpur-8 and Sarguja –1 (69) indicating that these varieties had higher divergence. It was minimum (13.166) between groups VIII and II followed by (13.241) between groups IV and III indicating they are very close to each other. A single variety Cluster VIII was noted to be genetically closer to multivariety Clusters II, I, IV and III and single variety Clusters; groups XII and XIII were closer while other single variety Clusters were highly divergent. In general, multivariety Clusters were found to be closer with each other.
The intra-cluster distance ranged from 0.0 to 11.70, the maximum being in Cluster V with only 3 genotypes, while Cluster IV with 13 genotypes recorded only 8.97 D2 value. In general, single genotypes recorded only 8.97 D2 value and thus these genotypes were found to be highly divergent as also evidenced from the character means for various Clusters.
The inter-cluster D2 values indicated that Cluster VII was the lowest for petiole length (0.695), pods/plant (0.167) and pod yield/plant (0.041). Cluster III was the highest for leaflet area (5.499) and Cluster II was the lowest (0.052). The same for pod length and 100-seed weight was the highest in Cluster VII (1.414) and the lowest in Cluster I (0.075) as also evidenced from the Cluster for pod length (17.05, 11.18). The trend in the case of 100-seed weight was similar in these two Clusters. The intra-cluster D2 value for days to flowering was the lowest (0.007) in Cluster-VI, while it was the highest (0.858) in Cluster VII. Cluster–IV has the highest D2 value for seed: pod ratio (2.028) and the lowest in Clusters V. Cluster IV had the highest D2 value for yield/plant (0.890) and it was the lowest in VII. The Cluster I had the highest (0.279) for protein content.
The highest contribution towards genetic divergence among the genotypes attributed to 100-seed weight (12.857%), seed: pod ratio (12. 38%) pod length (12.063%) and protein content (11.904%) whereas, pod width and yield/plant contributed minimum to divergence (5.555, 5.837%). This indicated that the protein content of the genotypes is as important as 100-seed weight and pod length in hybridization programme.
Data on 6 agronomically important traits were recorded in 48 strains collected from 8 Indian states. Using the Mahalanobis D2 Statistics, the strains were grouped into 10 clusters, with days to flowering, and number of pods/ bunch contributing most to genetic divergence. Most clusters included varieties from different geographical regions. Canonical analysis confirmed the D2 grouping
Twenty eight genotypes collected from different states including local landraces were tried at Keonjhar (Orissa) in 1994 and 1995 in randomized block with 2 replications. Observations were made on 8 characters and the data were analysed by applying D2 statistics. The genotypes were grouped into different clusters. Principal component analysis (Canonical) was done to know the relative contributions of different traits to the total variation.
Twenty eight genotypes fell into 5 clusters on the basis of D2 values. The distribution pattern of genotypes into clusters indicated that Cluster I was the largest containing 22 genotypes followed by Cluster III with 3 genotypes. Remaining 3 Clusters (II, IV and V) had a single genotype each. The members of the I Cluster had originated from different geographic regions and genetic divergence did not follow the same trend.
The intra–and inter-cluster average D2 values indicated that the geographical distributions could not be related to spatial patterns of the Clusters. Clusters II and V showed maximum divergence between them (285.61) followed by Clusters I and V (272.30) and clusters I and IV (194.06). Minimum divergence was observed between Clusters II and III (69.62), followed by Clusters II and IV (85.66). Cluster I (62.59) had higher intra–cluster D2 value followed by Cluster III (58.19). However, Clusters II, IV and V had no Cluster distance (0) as they were represented by a single genotype each. These results suggest that genetic drift and selection could cause greater diversity than geographic distance.
Differences in cluster means existed for almost all the characters studied. Cluster-I had low mean values for days to first flowering (63.91). Cluster-II had highest pods/plant as well as high 100-seed weight. Higher mean pod girth was associated with Cluster IV. Cluster V had maximum mean pod length, pod weight, seeds/pod and total green pod yield/plant.
The mean values of Canonical variates for Z1 and Z2 axes were obtained. The grouping of genotypes done on the basis of Mahalanobis D2 statistics was in conformity with the results of the Canonical analysis. The first Canonical root accounted for 49.89% and the second root for 23.20% of variation. These two vectors accounted for 73.09% of total genetic variation. Sum of all Canonical roots was 1332.68; value of first canonical root, 664.87; value of second Canonical root, 309.18; percentage of variation absorbed by first root is 49.89 and percentage of variation absorbed by second root is 23.20.
The germplasm resources of Dolichos lablab (Lablab purpureus) were investigated in the Quinling–Bashan mountain region, Sichuan. Some 32 germplasm accessions were collected. The distribution area of D. lablab, its cultivation, cultivar types and morphological characteristics are described. Four elite cultivars were recommended.
Lablab purpureus is a fast growing annual multipurpose legume in tropical and sub–tropical farming systems. The ripe seeds and green pods are being used as a vegetable in Asia, while in other tropical regions the whole plant is used as a green cover or as a forage for livestock. Presently, only Rongai and HighWorth released in Australia are being utilized for forage purposes and most of the research carried out on feed quality is focused on these two varieties. Both the Commonwealth Scientific and Industrial Research Organization (CSIRO) and the International Research Institute (ILRI) hold a large collection of forage types of this species. In order to establish a core collection of this tropical legume, a total of 251 accessions was grown in unreplicated, spaced rows at Zwai (Ethiopia – 125 accessions) or Redland Bay, Australia (126 accessions) to study the detailed morphological and agronomic attributes. In both the collections, there was a considerable variation in morphological attributes and a number of indigenous wild types from Africa have been identified in both the collections. While those held at ILRI were large – sized with one to two seeds and originated from Ethiopia, wild types from CSIRO collections had smaller seeds having originated from other East African Countries.
Genetic divergence was determined according to Mahalanobis D2 Statistics (Mahalanobis, 1936) and the genotypes were grouped into clusters. Inter–and intra–cluster distances were also calculated. The clustering pattern followed their respective geographical origin. This suggests that the obvious variation between the clusters might have resulted from the possible genetic drifts and selection.
As a consequence, the character constellations that might be associated with particular regions in nature, lose their individuality under human interference. It is, therefore, important to choose the parents from diverse sources based on D2 analysis rather than geographical isolation for development of improved varieties through hybridization.
The intra–and inter D2 values on pooled basis have shown that clusters IX, XII, XII, XIV and XV had a zero magnitude of intra- cluster distance as they were solitary. cluster VI showed maximum divergence (160.90). The other clusters remained in- between these two values. In the present study, the intra- cluster distance was maximum between cluster VIII and cluster XV (2313.60). This suggests that the genotypes from these clusters were highly divergent from each other. Similarly, clusters XI and XV were also quite diverse (2046.10). The minimum intra- cluster distance was observed between cluster II and cluster V (150.00) which indicates the closeness of the genotypes in these clusters.
The cluster means for 14 characters on pooled basis indicated that the solitary cluster CA with genotype GA-19 had the highest mean in respect of grain yield per plant, branches per plant and pods per plant. The cluster VIII exhibited lowest means for days to 50% flowering, days to maturity and inflorescence per plant. It could, therefore, be concluded that significant genetic diversity exists among 144 genotypes for most of the important characters. This could be explained on the basis of long term selection in different directions–natural and human. In this context, grain yield, pods per plant, inflorescence per plant, branches per plant and days to 50% flowering are the important characters contributing substantially to the genetic divergence. Hybridization between the members of the divergent groups might be rewarding in terms of crop improvement for better yield and quality as well as for early maturity and photo-insensitivity.
About 122 accessions were sown in Redland Bay experiment including cvs. HighWorth and Rongai, while the Zwai experiment contained 127 accessions. Characterization of all the 249 accessions was done using a common set of morphological and agronomic attributes. The data collected were analyzed using multivariate analysis and a classification constructed for each collection. Considerable diversity was observed in most of the attributes measured. Seed weight, time to flower and plant height were the most important attributes in determining group allocation in both classifications.
Sub–species uncinatus was clearly separated from the remainders of the collections in both the classifications. All other groups contained ssp. purpureus except for a few accessions with long, narrow pods of spp. bengalensis. Both collections had a high proportion of L. purpureus, spp. purpureus, especially accessions similar to the Australian cultivars Highworth and Rongai. The two classifications provided an overview of diversity and highlighted the similarities and dissimilarities between the two collections.
A range of maturity types and accessions with long pods, which have potential as dual purpose or grain crops for human consumption were included thus representing a whole range of morphological and agronomic diversity supporting the fact that Lablab has the capacity to become a multipurpose legume for both commercial and small holder agriculture. Cultivation of spp. uncinatus was rare and that landraces of this subspecies have a very restricted regional use. Some of the Ethiopian ssp. purpureus landraces collected from regional markets, semidomesticated and wild accessions from Southern Africa and wild accessions from India were also rare. With these observations, a core- collection of the germplasm was developed for better plant breeding and agronomic studies.
In Southern India the Dolichos beans are widely used as vegetable and a pulse as well. The crop has remained unexploited owing to low productivity, long duration, photosensitivity and indeterminate growth habit. However, with the use of existing germplasm.
Legumes are second only to grasses with more than 650 genera and 16,000 species. In Southern India the Dolichos beans are widely used as vegetable and a pulse as well. The crop has remained unexploited owing to low productivity, long duration, photosensitivity and indeterminate growth habit. However, with the use of existing germplasm, Shivashankar and Kulakarni (1989) developed determinate, early maturing and photoinsensitive varieties for Karnataka region in India. But the efforts to enrich the genetic resources and variability in this underutilized crop were minimal. Therefore, in kharif 2004–05, 237 accessions of Dolichos germplasm, collected from Karnataka and neighbouring states, were sown in kharif 2005 and were phenotypically characterized and documented.
All accessions of Dolichos bean differed significantly for all the seed traits such as seed length, width, thickness and 100 seed weight. Large variation was found for seed length which ranged from 7.515 to 12.873 mm and 100 seed weight from 21.00 to 30.00g. Further, 100 seed weight was significantly positively correlated (P<0.01) with the length and seed width. The germplasm was classified based on plant types: determinate types (156 accessions), indeterminate types (50 accessions) and semi-determinate (15 accessions). From these studies, it was concluded that the cultivated field types were mostly determinate and photoinsensitive types, while indeterminate types were spreading and photo – sensitive.
This study showed that Lablab purpureus L. var. <i class="italic">typicus</i > 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.