Heterosis studies in single crosses of inbred lines in maize (Zea mays L.)

Abstract

Information on heterosis is very important in the assimilation of desirable traits into maize (Zea mays L.) germplasm. Identification of suitable germplasm, knowledge of combining ability and heterotic group of the identified germplasm is a prerequisite in successful improvement of crop varieties. The objective was to assess the heterotic relationship among ten maize inbreds. The ten inbreds and their diallel crosses (45 F1’s) excluding reciprocals were evaluated for thirteen characters viz., days to 50% tasseling, days to 50% silking, days to 75% husk browning, plant height, ear height, cob length, cobs plant-1, kernel rows cob-1, kernels row-1, cob diameter, 100-seed weight, protein content and grain yield plant-1. The hybrids and a commercial check were evaluated across two locations in 2011. High level of heterosis over check was observed for grain yield and its component as well as other desirable agronomic traits. The most desirable cross combination viz., NAI-113 x NAI-123 for seed yield plant-1 also showed desirable heterosis for cob length, kernel rows cob-1, kernels row-1, cob diameter and 100-seed weight (over check). The cross combination W3 x W5 (ear height) NAI-143 x NAI-147 (cobs plant-1), W3 x NAI-142 (kernel rows cob-1), NAI-137 x NAI-143 (kernels row-1), NAI-152 x NAI-137 (cob diameter), W5 x NAI-116 (100-seed weight) and NAI-143 x NAI-116 (protein content) showed highest heterosis over check. The negative heterosis observed for maturity traits for some hybrids, coupled with high grain yield is a desirable attribute for hybrid production. W5 x NAI-116 was most desirable cross combination for early maturity coupled with other desirable traits. These cross combinations also revealed high per se performance.