Phaseolus lunatus

The Lima or Sieva bean, also known as the butter bean. Named after the capital of Peru, archaeological remains of this bean have been found there dating from 6000BC. However, it is thought that this bean probably originated in the Guatemala area of Central America and was taken to South America by early travellers. The green shelled beans are eaten as a vegetable, and the dried beans are also cooked and eaten. The plant is self-pollinating, but some natural cross-pollination occurs. Of interest to amateur breeders working with horizontal resistance. Phaseolus mungo

Black gram. This is a highly prized pulse in India. The flowers are self-pollinating and cross-pollination is very rare. Of local interest to amateur breeders who should commence by selecting within existing populations.

The wild progenitors of this crop are extinct. Phaseolus vulgaris

The haricot bean, also known as the French bean, common bean, kidney bean, salad bean, runner bean, snap bean, string bean, and frijoles. The species originated in Mexico and it shows great variation, with beans ranging in size from the small

'pea beans' to the large 'kidney beans', and with colours ranging from white through yellow, pink, brown, and red to black. The so-called 'pinto' beans are speckled brown. Both determinate and indeterminate plants occur.

This is the most widely grown species of Phaseolus and it is the most important single source of vegetable protein in the human diet. It offers great scope for amateur breeders working with horizontal resistance. In non-industrial countries, selection within existing landraces should be the first step. The plant is self-pollinated and, when hand-pollinating, some manual dexterity is required in emasculating the flowers. Late selection should be used.

An alternative approach is to use black beans as a genetic marker, using recurrent mass selection . If the breeding involves white beans, a mixture of white bean cultivars is planted in alternate rows with mixtures of black bean cultivar. About 1-5% cross-pollination will occur. The white beans are harvested and grown as a crop whose harvest is separated into white and black beans. The black beans, which are the product of cross-pollination, are then grown and harvested, and the white beans of that harvest are kept for late selection and eventual use as parents in the second breeding cycle. The black beans of that harvest are kept for use as parents in the second breeding cycle.

Virtually all bean breeding during the twentieth century has involved Pedigree breeding and vertical resistance. The exception is a horizontal resistance breeding program in Mexico, which has revealed both the great potential for the development of horizontal resistance, with an average 18% genetic advance in the early breeding cycles, and the feasibility of amateur breeding (See Garcia Espinosa, et al, Chapter 25, in Broadening the Genetic Base of Crop Production, Eds H.D.Cooper, C.Spillane, T.Hodgkin, ISBN 0-85199-411-3, CABI Publishing, 2001). The main diseases that will require use of the one-pathotype technique in order to inactivate all vertical resistances during screening are anthracnose (Colletotrichum lindemuthianum), and rust (Uromyces phaseoli). Other major diseases are bacterial blight (Xanthomonas campestris f.sp. phaseoli), halo blight (Pseudomonasphaseolicola), and bean mosaic virus. The insect pests include many aphids, white flies, leaf hoppers, and beetles. The Mexican bean beetle (Epilachna varivesta) is serious in Central America and the USA. The bean fly

(Melanagromyzaphaseoli) is important in Africa, Asia, and Australia. Phenotype

The observable properties of an organism produced by the interaction of its genotype and the environment. For example, recessive characters are part of the genotype, but they are not expressed phenotypically in the heterozygous state. And the Person-Habgood differential interaction is a phenotypic demonstration of a gene-for-gene relationship, but a genotypic demonstration would require inheritance studies in both the host and the parasite. Pheromone

A sex attractant chemical. These chemicals can now be synthesised, and used in insect traps to prevent sexual fertilisation, thus providing a control of some species of obnoxious insects. Phleum pratense

Timothy grass. One of the relatively few fodder grasses sown for grazing.

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Responses

  • Giacinto
    Are butter beans self pollinating?
    6 years ago

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