Development of a breeding method for durable resistance to angular leaf spot in common bean

作者：Ng'ayu Wanjau Beatrice N^*; Melis Rob; Githiri Mwangi; Sibiya Julia; Kimani Paul M

来源：Euphytica, 2016, 208(1): 91-100.

DOI：10.1007/s10681-015-1582-1

• Angular leaf spot
• Pseudocercospora griseola
• Durable resistance
• Minor genes
• Mixture of races
• Double cross population

Durable resistance, conditioned by minor resistance genes, has been described as more reliable in managing angular leaf spot (ALS) disease in the long term. The aim of this study was to develop a breeding method for durable ALS resistance in common bean and use it to accumulate minor genes into single genotypes. Four genotypes with intermediate resistance to ALS were selected from an initial 182 genotypes and used to generate a double cross segregating population. The F-1 was planted in a nethouse and inoculated with a mixture of races of the ALS pathogen. The genotypes that showed intermediate resistance to ALS were subsequently selected from the F-1 to the F-3 segregating populations. In the F-3 generation resistant plants were selected and the F-4 plants were evaluated, together with the parents and several market class varieties. Data were collected on ALS disease severity, seed yield, days to physiological maturity, seed size, seed colour and growth habit. Ten F-4 advanced lines with enhanced levels of resistance (disease score 1.9-3.2) were selected. These lines had improved resistance when compared to their parents (disease score 4.6-4.8) and market class varieties (disease score 5.4-8.2), which confirmed breeding progress for resistance to ALS. Simultaneous selection was done for seed yield, seed size, farmer preferred seed type and growth habit. The results of the study have shown that it is possible to develop ALS resistant common bean lines through the double cross method, using a mixture of ALS races.

• 出版日期2016-3