Heterosis and correlation deviations in maize under different agroecologies

Abstract

Forty-six early maturing single-cross hybrids developed from twenty-eight early maturing inbred lines along with national checks (Vivek QPM 9 and Vivek Maize Hybrid 43) were evaluated over three locations to identify the heterotic superiority of the new cross-combinations over the best check. Correlation studies were conducted to understand the shift in relationship between different agro-climatic zones. Nine single cross hybrids were found superior to the best check at all the locations. Even though more number of hybrids (60.4 per cent) was numerically superior to the best check over the locations of zone-1, only 13 hybrids exhibited more than 10 percent superiority in zone-1. Significant negative correlation was observed for grain yield with shelling percentage (–0.306*) and days to anthesis (–0.303*) and significant positive correlation was noticed with plant height (0.350*) in zone-1. Grain yield was significantly and positive correlated with shelling percentage (0.552**) in zone-2. A significant shift in correlation values was observed for grain yield with shelling percentage, plant and ear height, ratio of ear and plant height, anthesis-silking interval and grain filling period from zone-1 to zone-2. The correlation coefficients between characters which do not shift in their association over locations/zones are more reliable for breeding single cross hybrid adaptable to diverse climatic conditions. On the other hand, significant deviation in correlation coefficient may statistically determine the appropriateness of a location to an agro-climatic zone.