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Background: Association of several morphological traits such as trichome length and trichome density on the pod surface have been found to influence host plant resistance to insect pests. Genetic diversity analysis is used to identify the divergent genotypes and to utilize these genotypes to exploit heterosis. Further, morphological characters are stable across environments owing to oligogeneic nature, they serve as morphological markers in breeding which can be used in varietal or genotypic identification, varietal purification and even in seed production. Hence, the current study aimed to investigate on host plant resistance using portable paper microscope 'foldscope', genetic diversity and morphological characters. Methods: A total of 154 germplasm lines with three checks were evaluated in augmented block design (ABD) at Zonal Agricultural Research Station (ZARS), Kalaburagi, during kharif, 2018 to study their genetic diversity. Trichome length and trichome density were recorded using 'foldscope' 75 randomly selected genotypes, then correlated with shrivelled seed yield per plot due to pod fly incidence. Morphological characterization of 14 qualitative traits were recorded. Result: Grouping of 157 germplasm lines into twelve clusters indicated a wider genetic diversity for the traits studied, of which 7 clusters were solitary with one entry each. The genotypes with more trichome density and length had less damage by the pod fly. Large variations for morphological characters was observed among the genotypes for qualitative traits such as pod colour, stem colour, flower colour, seed morphology and pod trichomes. [ABSTRACT FROM AUTHOR]

The material for study of genotype x environment (G x E) interaction comprised of 23 genotypes, which were tested in four environments, during kharif-2012 and 2013 at two locations in Agricultural Research Station, Kalaburagi and Raddevadgi located in north eastern dry zone (Zone 2) of Karnataka. The experiment was laid out in lattice design with two replications. Highly significant differences among genotypes were observed for all the characters except number of pods per plant and yield per plant. Environmental +(Genotype x Environment) interaction was significant for days to 50 per cent flowering, day to maturity, plant height, pod bearing length, number of pods per plant and seed yield per plant. The variance due to pooled deviation was highly significant for all the characters which reflect the presence of sufficient genetic variability in the material. Stability parameters for seed yield per plant indicated that ASHA(ch) was stable and desirable, followed by RVK-275 and GRG-811 which were specifically adopted for favourable and poor environments respectively. Two years of field screening for Fusarium wilt (FW) and Sterility Mosaic Disease (SMD) yielded three genotypes viz., GRG-811, GRG-2009 and ASHA for resistance to Fusarium wilt and moderate resistance to SMD. Hence, these genotypes can be used directly as a variety or choice of parent for hybridization programme. [ABSTRACT FROM AUTHOR]

The present investigation was carried out during kharif 2012 at the Agricultural Research Station, Gulbarga and other four locations located in north eastern dry zone (Zone 2) of Karnataka, to know the stability of the nineteen advanced genotypes of pigeonpea. Highly significant differences among genotypes were observed for all the characters except number of pods per plant, number of seeds per pod and seed yield per plant. The variance due to Genotype x Environment found significant for the characters like days to 80% pod maturity and number of seeds per pod. Environment (linear) interaction component was significant for all the traits. The variance due to pooled deviation (non- linear) was highly significant for all the characters except for number of seeds per pod which reflect considerable genetic diversity in the material. Out of 19 genotypes studied two entries viz., GRG-109 and GRG-107 were consistent and high yielding compared to local checks. [ABSTRACT FROM AUTHOR]