Showing papers on "Mutation breeding published in 1999"

Mutation breeding for yield and Phytophthora infestans (Mont.) de Bary foliar resistance in potato (Solanum tuberosum L. cv. Golden Wonder) using computerized image analysis in selection.

Abstract: Using visual selection for off-types and image analysis to select against maturation mutants, a line combining improved late blight resistance and yield was isolated in an in vitro mutagenesis programme from a population of 2101 putative mutants. The adventitious regenerants from mutagenesis treatment, including spontaneous mutants (somaclonal variants), were subjected to serial subculture of the apical bud in vitro and two cycles of apical cuttings in vivo to breakdown chimeras. The selected line was stable in trials over five years; others were unstable or failed to combine improvement in late blight resistance with high yield. Leaf and tuber image analysis was used to characterize selected lines. Lines that differed most from cv. Golden Wonder in yield and late blight resistance were more easily distinguished from the control by image analysis. The role of image analysis in negative selection and in determination of the relatedness of mutants to the control is discussed.

Mutation breeding in improvement of Plantago ovata forsk

Abstract: Plantago ovata, a medicinal herb, requires improvement in seed yield to meet world demand for its seed husk. Mutation breeding has been attempted on account of the narrow genetic base of the crop. Two mutagens, gamma rays and ethylmethane sulphonate, were tried. The result obtained in all three replicates revealed that 20 kR dose of gamma rays boosted seed yield by more than 200%. The experiments were repeated during years between 1993–1995 and the results were confirmed. These results recorded a breakthrough in a crop not amenable to other techniques for improvement and are of great commercial value.

Development and prospect of plant mutation breeding induced by aviation and spaceflight in China

Abstract: Since 1987, about fifty species, three hundred varieties of crops have been sent in recoverable satellites or high altitude balloon (HAB). The selected lines include a high-yield, disease-resist, and hybrid-vigorous rice line, a recovered line of Japonica rice restoring sterility of Indica rice, a new green pepper strain which grows fruits over 500 g, a disease-resist, high-quality tomato line, a big-pod rape line, a big-fruit white lotus line and a big-bulb lily. The special conditions in the outer space can induce a variety of mutations in the plants and their progeny, which provides a new way for the plant breeding.

Genetic breeding and selection of mangoes in Pakistan

Abstract: Mango (Mangifera indica) belong to the family Anacardiaceane whose 40 species are found in South Asia and 13 of them are cultivated for edible fruits. The Mangifera indica varieties in Sindh are: Sindhri, Banganpali, Sawarnarika, Neelum, Desarhi, Langra, Alphonso, Siroli, and Chaunsa. Due to genetic erosion and biological diversity it is important to conserve the germplasm and improved rootstocks of mangoes and improve these varieties further, having desirable characters by genetic principles which help in plant breeding method e.g self and cross pollinated methods for breeding, breeding for disease resistance, breeding for quality trials and mutation breeding. There are mangoes ehich are self sterile and these could easily be used for crossing with various varieties of good characteristics. Plant breeding process require considering various factors e.g physiological (biomass, leaf area, specific leaf color and weight) and morphological characters e.g (flowering pattern, number of mature seed, vegetative growth which directly or indirectly influence on yield.) The selection of mangoes with desire characters is necessary, as it helps in removing inferior types and those prone to physiological disorder and select those varieties having greater market appeal and better cost benefits ratio. Plant science and biotechnology can improve mangoes production in various ways like: Making planting material available -Use of improved nursery practice -Development of new varieties (cultivars) -Breeding of new trials -Improvement of growth rate and yield -Management of root-stock -The selection and breeding practice depend upon: Regula cropping with good yields under favourable condition -Developed graft plants -Time of maturity, extension of ripening season -Attractive skin color -Fruit quality, taste, nutritional value -Mango rootstocks with tolerance to saline condition -Pest and disease susceptibility -Precocious bearing -Better harvesting methods -Tree growth and habit given more leaf to wood ratio -Regular bearing -Reduced amount of exuded sap. Tissue culture and somacloning could provide both rapid propagation of clones, plus an area for possible mutation manipulation particularly for selecting disease resistance. Cultivars propagated by stone grafting, veneer grafting and inarching grow faster than those propagated by stooling and air layering.