Screening for seed fertility and ploidy in Musa spp

Abstract

Musa species (spp) comprise genotypes with varying ploidy and fertility levels which limit seed production and damper its improvement. This study was aimed at assessing the ploidy and fertility of 11 Musa accessions in the germplasm held at Ebonyi State University, Abakaliki, through crosses, using artificial hand-pollination to generate hybrids. The ploidy levels of the accessions were determined by assessing their chloroplast density in pairs of stomatal guard cells. Fertility was assessed by crossing, following North Carolina II Mating Design, whereby males (Calcutta 4 and PITA 14) were used to fertilise females (‘Agbagba’, ‘Efol red’, ‘Efol’, ‘Owom’, ‘Numbrantor’, ‘Atagafong’, ‘Nblepaul’, ‘Aging’ and Sh3436). For ploidy determination, chloroplast numbers of accessions were significantly different at p ≤ 0.05, and revealed that 18.18% were tetraploid (males), 72.73% were triploid females (except ‘Efol red’) and 9.09% were diploid (‘Efol red’). For the fertility assessment, the crosses did not generate seeds. This could be attributed to triploid nature of most accessions, which favours nondisjunction during meiosis, hereby, producing sterile gametes. To enhance seed generation in Musa crosses, ploidy nature should be among the basic determinants in assigning parental roles to accessions.