Segregation of vegetative and reproductive traits associated with tuber yield and quality in water yam (<i>Dioscorea alata</i> L.)

Abstract

Water yam (Dioscorea alata L.) is an important source of food for millions of people in Africa, Asia, South America, Caribbean and the South Pacific islands. Genetic mapping populations of this species have been produced as part of efforts to raise the efficiency of breeding through development and use of molecular markers. In this study, an F₁ mapping population (AM1) of D. alata, exhibited segregation for both tuber yield- and quality- related traits when evaluated in the field for 12 agronomic characters: days to shoot emergence, number of primary vines per plant, days to flowering, flower sex, flowering intensity, days to tuber initiation, number of tubers per plant, tuber yield per plant, tuber shape, bulbil formation, tuber browning and reaction to anthracnose (Colletotrichum gloeosporioides Penz) infection. The number of tubers/plant and the number of primary vines/plant were moderately positively correlated, while most of the other quantitative traits were weakly correlated with each other. There were more males (49%) than females (19.9%) identified in the population, however more than a quarter of the population (31%) did not flower and their sexes could not be determined. 20% of the progeny was resistant or tolerant to field infection by anthracnose. Population AM1 will be a valuable resource as a mapping population for genetic analysis and molecular marker development for tuber quality and several other agronomic traits in D. alata. 

Keywords: Flowering intensity, marker assisted breeding, mapping population, phenotypic variation and trait segregation, tuber yield and quality, water yam

African Journal of Biotechnology Vol 13(28) 2807-2818