Читать книгу Dry Beans and Pulses Production, Processing, and Nutrition онлайн

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Attempting to transfer yield potential from black beans to enhance yield of kidney beans was met with limited success, as a determining factor in bean breeding is seed size that corresponds with market class (Kelly et al. 1998). Kidney beans with one of the largest seed sizes (60g/100 seed) are generally lower yielding than small‐seeded black beans (20 g/100 seeds). In addition to genetic differences, each gene pool utilizes different physiological mechanisms to produce yield. Adams (1967) demonstrated the concept of yield component compensation in dry beans, where gain in one yield component was generally reflected by losses in another. Thus, selection for large seed size will result in either fewer pods per plant or fewer seeds per pod, either of which contributes to less yield. Limited genomic recombination is another factor limiting the exchange of genetic diversity between the gene pools. Segregation distortion is common in inter‐gene pool crosses (Blair et al. 2003) and the existence of incompatibility genes that result in gamete elimination in the species have also been suggested (Checa and Blair 2008). As a result of these gene pool incompatibilities, little progress has been made in the breeding of Andean type beans. Only modest gains in performance have been reported over years of breeding kidney and cranberry bean classes in the US. This lack of success has resulted in decreased acreage being planted to kidney and cranberry beans in the US. Likewise, the dominant bean class in Brazil is the MA carioca bean that was introduced in the late 1940s and has replaced the traditional large‐seeded Andean Jalo seed types. There is some optimism that new molecular tools and technologies might provide opportunities to correct this limitation in breeding Andean beans. Expanded crossing with landraces within the gene pools is a recommended strategy (Gioia et al. 2019) to increase genetic diversity that is being implemented (Cichy et al. 2015) for Andean beans. An alternative approach is to use the wild species with its “hidden” genetic potential rather than trying to focus on recombination within or between species where these gene pool incompatibilities exist.