Developing hybrids from two improved maize populations

The performance of a group of 49 hybrids from seven elite maize (Zea mays L.) lines selected from each of the two populations, BSK(S)C5 and BSSS(R)C5, was compared with the varietal-cross hybrid of the source populations and with elite single-cross hybrids. Both populations had been improved by five cycles of recurrent selection. BSK(S)C5 was improved by S 1 selection from BSK; whereas BSSS(R)C5 was improved by reciprocal recurrent selection from BSSS with BSCB1 as the tester.The mean yield of all hybrids was statistically higher than the mean yield of the varietal-cross hybrid and approached the yields of the checks, indicating that early testing in phase 1 was effective. Nine hybrids were significantly higher yielding than the varietal cross, and their yields were similar to those of the checks. The best hybrid outyielded the varietal cross by 18%.The data obtained from this study indicate that improved populations developed from recurrent selection programs should be useful sources for improved conventional hybrids when the varietal cross yields at least 90% as much as the better current hybrids.