Diallel analysis of resistance to bacterial stalk rot caused by Pectobacterium chrysanthemi pv. zeae Burk., McFad. and Dim. and other agronomic traits in corn (Zea mays L.)
2004
Subekti, N.A.
Diallel analysis was employed to determine the genetics of resistance to bacterial stalk rot in six corn inbred lines. The crosses were made among three resistant, one moderately resistant, and two susceptible lines at UPLB during 2002 wet season and 2003 dry season. The parents, F1 crosses, and F1 reciprocals were evaluated using Randomized Completely Block Design (RCBD) with two replications at IPB [Inst. of Plant Breeding, College, Laguna, Philippines\} during 2003 wet season. Diallel analysis of resistance to bacterial stalk rot was conducted using Griffeng's Model I, Method I. Additive gene effects were found to be more important than non-additive gene effects in the expression of resistance to bacterial stalk rot in corn. Two resistant parents, S3YB 137-1-1-B and TUPI (S3) 5-1-B, exhibited the best general combining ability for resistance to BSR. The cross between these two parents and the cross between TUPI (s3) 5-1-B and 97-835 resulted in the best specific combination for resistance to BSR. Good SCA estimates were also found for days to silking and yield. Additional favorable agronomic traits attributed to these crosses were ideal ear height relative to the plant heightgood score of plant aspect, husk cover, and ear aspectand relatively lower grain moisture content compared to their parents. Based on the results of this study, recurrent selection, which mostly exploits additive gene effect, could be an effective approach to increase the level of resistance to BSR in synthetic or composite populations. The improved cycles of the population can then be used as source for hybrid breeding.
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