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University of Nairobi (2008)

Combining ability for grain yield and agronomic traits among early drought tolerant quality protein maize (QPM) inbred lines

Musila, Ruth Nzisa

Titre : Combining ability for grain yield and agronomic traits among early drought tolerant quality protein maize (QPM) inbred lines

Auteur : Musila, Ruth Nzisa

Université de soutenance : University of Nairobi

Grade : Master of Science 2008

Résumé
Quality protein maize (QPM), a bio-fortified form of maize has twice the content of limiting amino acids, lysine and tryptophan, compared with conventional maize. It has been developed to, among other uses, help alleviate human malnutritition in areas where protein deficiency is a major problem in diets as in the dry areas of Eastern Kenya. Information about how F 1 hybrids produced from early drought tolerant QPM inbred lines compare with one of the popular QPM single-cross (CMLI44/CMLI59) is likely to speed up release of early drought tolerant QPM cultivars in this area. Prior knowledge on the combining ability of these inbred lines would be beneficial to breeders in deciding how to best develop single-crosses, three-way, double-cross hybrids and synthetic varieties. The objectives were to (i) compare grain yield and agronomic performance of F 1 hybrids produced from early drought tolerant QPM single-crosses with a reference QPM check (CMLI44/CMLI59) ; (ii) estimate general combining ability (GCA) and specific combining ability (SCA) among early drought tolerant QPM inbred lines for grain yield and other agronomic traits ; (iii) assess the relative importance of general combining ability and specific combining ability in determining the progeny performance of the early drought tolerant QPM inbred lines ; (iv) to predict grain yield of three-way and double-cross hybrids from data obtained from the early drought tolerant singlecrosses ; and (v) to establish the relationship between grain yield and other agronomic traits. Fourteen inbred lines were crossed in half diallel mating design. The 91 diallel hybrids together with 18 experimental checks and one reference check were planted in one trial and evaluated in five environments in Kenya including under four optimum and one drought condition. Data on grain yield, time to anthesis, time to silk, anthesis-silking interval, ears per plant, root lodging, stalk lodging, ear rots and ear aspect were recorded. The experimental checks yielded more grain than the diallel hybrids. One diallel hybrid entry 3 and one experimental check entry 72 had higher grain yields and were earlier in maturity than the reference check. The combined analysis of variance showed that the mean squares due to genotypes and general combining ability (GCA) were significant (p

Mots clés : Maize ; Zea mays ; Drought ; Genetics ; Proteins

Présentation - http://erepository.uonbi.ac.ke/handle/11295/20559

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Page publiée le 10 décembre 2013, mise à jour le 23 mars 2018