SUCCESSES AND CHALLENGES OF THE BEAN BREEDING PROGRAM OF THE ARC-GRAIN CROPS INSTITUTE, SOUTH AFRICA

摘要

The bean breeding programme of the ARC- Grain Crops Institute concentrates on two main seed types, namely red speckled sugar (RSS) and small white canning (SW) beans, with dark red kidney (DRK), large white, painted lady, carioca & Phaseolus coccineusfilling niche markets. The programme consists of three branches, namely the main breeding programme and the bacterial and fungal resistance breeding programmes. The main breeding programme creates new variability, sets standards for adaptation and increased yield, quality and field resistance to diseases. The breeder makes crosses to improve yield and quality. Greenhouse increases are followed by field selection, then evaluation in yield trials. This is reliable when done over multiple sites and seasons. The breeder also undertakes field evaluation of disease resistance. However, except for BCMNV (which is now successfully controlled) this is unreliable due to uneven infection and the presence of races in some diseases. The main breeding programme also supplies the well adapted cultivars for backcrossing, the most important of which are the red speckled sugar cultivars Kranskop, Jenny, OPS-RSI, -RS 2, -RS 4, -RS 5, and -RS 6 and the small white cultivars Teebus, Helderberg and OPS-KW 1. The breeder evaluates lines from both resistance breeding programs against the yield and quality standards and releases any promising line as a cultivar. The breeder is also responsible for the national cultivar trials and increases of breeder's seed.