Resistance of arcelin incorporated bean (Phaseolus vulgaris L.) hybrids and their parental cultivars against the bean bruchid Zabrotes subfasciatus (Boh)

Abstract

A hybridization bean breeding programme aimed at breeding beans resistant against the bean bruchid species Z. subfasciatus which destroys beans in storage was carried out at Sokoine University of Agriculture (SUA) Morogoro. Tanzania between 1994-1997. Five potential local bean varieties/lines were crossed to a bruchid resistant bean line RAZ 24-2 which was developed at SUA by selection from ClAT segregating RAZ bean populations. Seeds of RAZ lines contain arcelin a protein which confers resistance against Z. subfasciatus and can be transferred into other varietiess by hybridization. The backcross breeding procedure was adopted and five arcelin containing progenies were developed from this breeding programme. Seed of the developed progenies and those of the parents were then tested for resistance against Z. subfasciatus a randomized complete block design with 5 replications. There were significant difference, (P < 0. 05) in resistance against Z. subfasciatus among the genotypes. Results indicated that arcelin incorporated genotypes were superior over the arcelin deficient parents for resistance against Z. subfasciatus. Generally, the presence of arcelin in bean seeds delayed bruchid development reduced the number of emerged bruchids damage on bean seeds. However, bruchids managed to lay many eggs on seeds of all cultivars tested suggesting that bruchids are not inhibited from laying eggs on archelin containing seeds.