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Abstract:The field experiment was carried out using 121 germplasm lines of rabi sorghum to study association among the yield and its component traits, direct and indirect effects of traits on the yield. Association studies indicated that at both genotypic and phenotypic levels, panicle width (rg=0.190; rp=0.204) and 1000 grain weight (rg=0.450; rp=0.520) showed significantly positive correlation with grain yield per plant. Genotypic correlation magnitude was higher than phenotypic correlation. Partitioning of yield and yield components both at phenotypic and genotypic levels into direct and indirect effects revealed that the characters that had positive direct effects on grain yield were 1000 grain weight (Ppi=+0.3085, Pgi=+0.4621), panicle length (Ppi=+0.1516, Pgi=+0.2843), days to maturity (Ppi=+0.1539, Pgi=+0.1391) at both genotypic and phenotypic level. On grain yield indicating importance of these characters hence, due consideration should be given to these characters while planning a breeding strategy by utilizing rabi sorghum.

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.

Phytic acid is the major storage form of phosphorus in cereals. It binds with nutritionally important metals and affects mineral bioavailability. The present study analyzed phytic acid, inorganic phosphorus (IP) content, seed weight, and grain yield in 98 sorghum landraces and varieties grown in two environments to evaluate genotypic and environmental effects and to determine trait stability. Genotypic effects and genotype × interaction were significant for phytic acid concentration and yield components. A promising landrace, Malkhed-1, had the lowest phytic acid (0.015 mg g −1 ) concentration, with a higher yield (70.02 g plant −1 ), than the check variety M-35-1 in both environments. Similarly, among the varieties, Phule Maulee showed the lowest phytic acid (0.07 mg g −1 ) and a higher grain yield of 53.15 g plant −1 in both environments. Phytic acid and IP were negatively correlated (r = −0.34), whereas grain yield and seed weight were positively correlated (r = 0.20). Cluster analysis based on seed phosphorus traits and yield components identified five and six clusters, respectively. Genotypes containing low phytic acid with high yield identified in this study would be helpful for increasing the bioavailability of mineral nutrients.