No abstract

The research entails morphological characterization of pigeonpea genotypes based on qualitative traits which aids in varietal description and ensure genetic purity. The study was conducted at the Department of Pulses, Tamil Nadu Agricultural University during kharif, 2019 and rabi, 2019-2020. The experiment was conducted in Randomized complete block design with two replications. The 68-short duration pigeonpea genotypes were characterized and grouped based on 17 qualitative traits. The morphological characterization revealed that, more variation was identified for traits viz., pattern of streaks on standard petal, plant height, seed colour, seed shape and seed size. Sixty - eight genotypes were subjected to cluster analysis and were grouped into four major clusters with an average similarity of 80%. The similarity coefficient ranged from 0.65 to 1.00. The cluster I consisted of 60 genotypes. Two sub-groups were formed from Cluster I. The sub-group I had 59 genotypes at 84 per cent similarity, whereas the sub-group II consisted of the genotype ICPL19050. Cluster II was made up of six genotypes. The cluster II was divided into two sub-groups at 84 per cent similarity. Clusters III and IV were solitary clusters, each with a single genotype. The characterization of genotypes with specific traits could be used to identify the genotypes, maintenance of genetic purity and to utilize in future breeding programmes.

Background: Absolute understanding of the relationship between yield and yield attributing traits contributing to variance is predominant in a breeding programme. To study the multivariate analysis and interrelationship among the yield and yield attributing traits in the pigeonpea, 68 genotypes were subjected to principal component analysis and association studies. Methods: The 68 pigeonpea genotypes were raised during two seasons viz., rabi, 2019-2020 and rabi, 2020-2021 in a randomized complete block design with two replications. The two-season data was pooled and utilized for multivariate and association studies. Result: The total variance was split into 12 principal components. Four principal components were found to have eigen values more than one and explained 78.75 per cent of the total variance. The correlation studies revealed that, the single plant yield was highly correlated with the traits viz., days to 50 per cent flowering (rg=0.213, P less than 0.05), days to maturity (rg=0.347, P less than 0.01), plant height (rg=0.536,P less than 0.01), number of branches per plant (rg=0.331,P less than 0.01), number of clusters per plant (rg=0.705,P less than 0.01), number of pods per plant (rg=0.805,P less than 0.01), pod length (rg=0.481, P less than 0.01), number of seeds per pod (rg=0.231, P less than 0.05) and hundred seed weight (rg=0.505, P less than 0.01). Selection for these traits will improve single plant yield. Path analysis showed that the traits viz., number of pods per plant (0.871), shelling percentage (0.391) and hundred seed weight (0.744) had high positive direct effect on single plant yield, whereas the high indirect effect on single plant yield possessed by number of pods per plant through traits viz., days to maturity (0.316), plant height (0.421), pod bearing length (0.454) and number of clusters per plant (0.706).

The three short duration cytoplasmic genetic male sterility (CGMS) hybrids developed using A 2 (Cajanus scarabeoides) cytoplasm-based male sterile lines (CORG 990047A, CORG 990052A and CORG 7A) and the restorer inbred AK 261322 and their segregating populations (F 2 and BC 1 F 1 ) were subjected to the study of inheritance of fertility restoration in pigeonpea. The fertility restoration was studied based on three different criteria, namely, anther colour, pollen grain fertility and pollen grain morphology and staining. The F 2 and BC 1 F 1 populations of the three crosses, namely, CORG 990047A Â AK 261322, CORG 990052A Â AK 261322 and CORG 7A Â AK 261322, segregated in the ratio of 3:1 and 1:1, for anther colour (yellow:pale yellow), pollen grain fertility (fertile:sterile) and for pollen grain morphology and staining. The above study confirmed that the trait fertility restoration was controlled by single dominant gene. This finding can be utilized for the identification of potential restorers, which can be further used in the development of CGMS-based hybrids in pigeonpea.

Genetic analysis and diversity study was done involving 68 early duration pigeonpea based on 12 quantitative traits. The genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) was high for traits viz., plant height (20.22, 20.77 %) pod bearing length (22.14, 23.44 %), the number of clusters per plant (23.03, 25.06 %), the number of pods per plant (21.21, 23.64 %) and the single plant yield (23.61, 34.89 %). The traits viz., plant height (94.77, 40.54 %), the number of branches per plant (78.20, 31.04 %), pod bearing length (89.18, 43.07 %), the number of clusters per plant (84.49, 43.61 %), the number pods per plant (80.51, 39.20 %) and 100 seed weight ( 94.37, 29.56 %) existed high heritability combined with high genetic advance as a proof for additive gene action and aiding in selection of these traits. The 68 pigeonpea genotypes were grouped into seven clusters based on Mahalanobis D 2 statistic. The cluster II contains the maximum number of genotypes (44 genotypes) followed by cluster V with 10 genotypes. The maximum inter cluster distance (22.18) was observed for clusters VI and VII and the minimum distance (7.76) was between clusters III and IV. The cluster II recorded the maximum average cluster mean for traits viz., plant height (143.02 cm), pod bearing length (83.47 cm), the number of cluster per plant (91) and single plant yield (41.79 g). The lowest average cluster mean for single plant yield (27.42 g) and the yield attributing traits viz., the number of clusters per plant (60), the number of pods per plant (112) was observed for cluster I. The highest per cent contribution to genetic diversity is rendered by days to fifty per cent flowering (21.12 %) and the lowest contribution is observed for pod bearing length (0.83%). The genotypes CO2R (61 days) of cluster VI and ICPL19024 (64 days) of cluster I had reduced days to fifty per cent flowering and can be utilized in the breeding of early maturing pigeonpea genotypes. The genotypes viz., ICPL19002, ICPL19004, ICPL19007, ICPL19009, ICPL19010, ICPL19018 and ICPL19028 were found to be superior for yield and yeld attributing traits.Genotypes identified in the present study, could be used to develop varieties with early maturity and increased yield in pigeonpea.