Combining Ability among Twenty Insect Resistant Maize inbred lines Resistant to Chilo partellus and Busseola fusca Stem borers
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Date
2009-01Author
Karaya, H.
Njoroge, K.
Mugo, S.
Nderitu, H.
Type
ArticleLanguage
enMetadata
Show full item recordAbstract
A partial diallel design was used among 20 maize inbred lines to form 110 F1 hybrids to generate
information on the values of these lines for developing insect resistant maize varieties during the short
rains season of 2006. The hybrids were evaluated for resistance to the C. partellus and B. fusca, and
for agronomic performance over two seasons during long and short rains of 2007 at a mid-altitude dry
early maturity site at KARI Kiboko, and the moist mid-altitude medium maturity site at KARI Embu.
leaf damage score (using a scale of 1-9 where: 1= No damage and 9= extremely damaged), number of
exit holes, cumulative tunnel length, and grain yield were measured as resistance traits. The genotype
sum of square was partitioned into general combining ability (GCA) and specific combining ability
(SCA) effects. Maize inbred lines with good general combining ability for insect resistance including
maize inbred lines with significant and negative GCA`s for leaf damage were identified as lines
12,16,18,19 and 20 at Kiboko and lines 8, 17, 18, and 20 in Embu. Results showed that the problem
of stem borers intensified by over 40% within four years in the experimental region of Eastern Kenya;
currently mean yield loss due to stem borers was assessed to be about 56%. Several hybrids had
significant negative SCA for leaf damage and significant positive SCA for grain yield. The maize
inbred lines studied revealed their potential for use in breeding programs for insect resistance that
could result in a correlated response for increased grain yield. Recurrent selection would be the best
option to develop high yielding insect resistant germplasm for this region of Kenya considering that
additive gene action were predominant. Evidently, it would be more difficult to develop host plant
resistance to B. fusca than to C. partellus.
Citation
International Journal of Plant Production 3 (1), January 2009Publisher
GUASNR International Maize and Wheat Improvement Center (CIMMYT),Nairobi Kenya. University of Nairobi, Faculty of Agriculture, Upper Kabete Campus, Nairobi Kenya.