Indian Agricultural Research Institute, New Delhi
A genetic analysis of reaction to stem borer was carried out using design II of Comstock and Robinson (1952). Four male sterile lines and sixteen male parents along with their 56 crosses were included in this study.
The female parents did not differ in resistance (perhaps due to the common source of milo cytoplasm) but the male parents were different in reaction to primary and secondary damage of borer. There was no heterosis for primary damage. It also revealed that there were independent mechanisms for primary and secondary damage and these were quantitative in nature. General combining ability was predominant for resistance to primary damage while specific combining ability was 1.5 times more for secondary damage. The further partitioning of heterosis showed that the non-linear component was substantially high in comparison to the linear component both for primary and secondary damage. Thus line performance per se could not be considered as the indicator of hybrid performance.
The dwarf and early varieties showed resistance to primary damage while tall and late maturing varieties were resistant to secondary damage of stem borer.
