Chinese adzuki bean germplasm: 1. Evaluation of agronomic traits

A core collection of adzuki beans, representing the germplasm of Chinese la nd races, was screened at Warwick Australia in a replicated yield trial sow n mid-summer. Grain yield, yield components, phenologic traits, vegetative characteristics, and morphologic descriptors were recorded for all accessio ns plus Japanese-derived check varieties. Accessions from southern China were later flowering, had smaller seed, and grew taller than those from central China. Grain yield was greatest for acc essions from central China, whereas both north Chinese and Japanese check a ccessions were generally low yielding. The evaluation of diversity displayed trends associated with latitude of ge rmplasm origin, which were positive or negative according to the trait. Sim ilarly, the germplasm diversity in duration of crop growth phases and in ra te of yield expression was also associated with latitude of landrace origin . Localised variations from these trends were found for seed size and for num ber of pods per plant. Various trends with latitude of origin were found fo r natural incidence of powdery mildew, for growth habit, plant height, vini ng and leaf colour. However, traits not associated with latitude of germpla sm origin included primary and secondary seed colour, mature pod colour, an d degree of branching. The evaluation suggests that selections from this greater range of genetic diversity may allow higher yielding varieties than the current Japanese-der ived standards to be developed for Australia.