Estimating heterosis and heterobeltiosis in phenological and vegetative traits and correlations in Musa diploid x diploid crosses

Abstract

This study was conducted to determine the extent of heterosis and heterobeltiosis in phenological and vegetative traits in Musa diploid by diploid crosses. The experimental design was RCB with two replications of 6 plants per genotype. Planting was done in alleys of multispecies hedgerows in an area of 2,880 m2 at a spacing of 3 m x 2 m. The study was conducted at the International Institute of Tropical Agriculture (IITA) High Rainfall Station, Onne, Rivers State, Nigeria for 3 years. Six female diploid banana and plantain clones (maternal/ seed parents) were crossed with a single diploid male plantain accession, TMP2x 2829-62 (paternal/pollen parent). The resulting diploid F1 embryos were cultured in vitro for 6 weeks and their seedlings along with the parental clones, vegetatively propagated from the parents of each genotype, were planted in the field. Data collected included days to flowering, time to fruit filling, plant height, plant girth, and height of next tallest sucker. Data subjected to ANOVA in RCB was tested at 5% level of significance. Heterosis (Ht) and heterobeltiosis (Hbt) were estimated. The degree of heterosis and heterobeltiosis differed for different traits, different crosses and genotype. Overall, 66.7% of the progenies showed heterosis and heterobeltiosis for days to flowering and time to fruit filling; 66.7% exhibited heterosis and 50% heterobeltiosis for plant height; 33% heterosis and heterobeltiosis for plant girth and 16.7% heterosis and heterobeltiosis for height of next tallest sucker. Correlations between the levels of heterosis for different traits between the progeny and the female parents were generally weak except for time to fruit filling (r = 0.816) which showed a significant correlation. Heterosis and heterobeltiosis occur in phenological and vegetative traits in diploid x diploid crosses indicating their importance in further possibilities for breeding.