Search Results
Abstract
Inheritance of an indehiscent anther (ia) mutant in the common bean (Phaseolus vulgaris L.) was studied. Dehiscence was incompletely dominant in heterozygotes making classification difficult in backcross and F2 populations. Progeny tests were necessary to determine that the character was conditioned by a single recessive gene. The symbol ia is proposed to denote the indehiscent anther gene.
Abstract
Worldwide interest in the winged bean [Psophocarpus tetragonolobus (L.) D.C.] as a food legume has increased in the past decade (6). The crop has the potential for greatly improving human nutrition needs in the tropics due to the relatively high protein content of the seeds (30–42%) and tuberous roots (8–20%, dry weight basis) and the fact that all plant parts except the stem are edible (4). It also is grown as a cover crop or green manure crop and is useful for livestock feed (5).
Abstract
A mutant with indehiscent anthers (IA) was found in the common bean, Phaseolus vulgaris L. The IA character was associated with absence or modification of the longitudinal anther suture, which resulted in nearly complete failure of anther dehiscence and self-pollination in IA plants. Pollen from IA plants was fertile, and normal pod and seed production was achieved by crushing the anthers and hand-pollinating either mature buds or flowers. Conventional cross-pollinations using freshly opened flowers on IA plants resulted in a low incidence of selfing. In a field planting of IA and normal plants, 94% outcrossing was measured in IA plants.
Abstract
Photoperiod-sensitive (short day) plants were found in okra [Abelmoschus esculentus (L.) Moench] PI 291124. These plants did not flower at Charleston, S.C., until mid-October. Segregation of populations derived from crosses with ‘Clemson Spineless’ (CS) indicated that photoperiod sensitivity was conditioned by a single recessive gene. Inheritance of hirsute seed, found in PI 172677, was determined by 2 separate genetic systems. The F1 of PI 172677 (hirsute) × ‘C S’ (glabrous) had hirsute hila and glabrous testae. In the F2, when data from seed parts were analyzed separately, hirsute hila was conditioned by 2 dominant genes, and glabrous testae was conditioned by 2 other dominant genes. When data on both seed parts were combined and independent assortment was assumed, 4 expected phenotypes were missing in the F2. Indirect evidence from the F2 and backcross populations indicated that there were linkages among the alleles which determine presence or absence of trichomes on okra seed. The possible linkage groups are described. An albino mutant, found in progeny of irradiated ‘CS’, was conditioned by a single recessive gene. The gene symbols sd and a are proposed for the genes conditioning the short day response and the albino mutant, respectively; the genes conditioning hirsute seed will not be named until linkage relationships can be resolved.
Abstract
Differences in water absorption by intact seeds and in osmotic properties of excised seed coats were measured in 4 near-isogenic breeding lines of snap bean, Phaseolus vulgaris L. White seeds absorbed water more rapidly than colored seeds. Excised white seed coats were more permeable to water than colored seed coats in response to an osmotic gradient. Seed coat thickness and seed coat dry weight were negatively correlated with rate of osmosis through the seed coats. Colored seeds had greater seed coat dry weight and thickness than white-seeded isolines.
Abstract
A method was developed to evaluate snap beans, Phaseolus vulgaris L., for resistance to root-knot nematodes, Meloidogyne spp., which permits selected plants to survive, making either hybridizations or seed increase possible in the same generation. Nematode inoculum are added to commercial potting medium in greenhouse benches and snap beans are grown either in peat or clay pots filled with uninoculated soil and buried in the inoculated media. Roots protruding through holes in the bottom of the pots are evaluated for root gall and reproduction indices.
Abstract
Breeding line B4000-3 is a white-seeded, bush-type snap bean (Phaseolus vulgaris L.) developed by the U. S. Vegetable Laboratory (USVL). B4000-3 has several characteristics of value to snap bean breeding programs. It has been tested for several seasons throughout the United States and has shown adaptation to diverse environments.
Abstract
Four snap bean (Phaseolus vulgaris L.) breeding lines, resistant PI 165426, and 2 susceptible commercial cultivars were tested for resistance to root galling and root-knot nematode (Meloidogyne incognita (Kofoid & White) Chitwood) reproduction under greenhouse and field conditions. Root gall indices, reproduction indices, and numbers of eggs/g of root were significantly less on resistant lines than on ‘White Seeded Provider’ in 2 greenhouse tests. In field tests, soil treatment with the nematicide DBCP resulted in significant control. In nontreated plots, resistant bean lines had less root galls than ‘Early Gallatin’. Plots planted with resistant lines had fewer M. incognita larvae than those with ‘Early Gallatin’. Mean yield of pods from resistant lines in nontreated soil was about 3 times the yield of ‘Early Gallatin’. Yield of pods from treated and nontreated subplots were not significantly different. These results indicate that resistance is equivalent to soil fumigation for root-knot nematode control in snap beans.
Abstract
‘NemaSnap’ is the first bush snap bean cultivar with resistance to the southern root-knot nematode, Meloidogyne incognita (Ko-foid & White) Chitwood. ‘NemaSnap’ is a useful bean for home and market gardens infested with large populations of root-knot nematodes due to continuous cropping with susceptible vegetable species. ‘NemaSnap’ offers a viable alternative for those who may not wish to use nematicides or who may be unable to obtain effective, restricted-use nematicides.
Abstract
Breeding line B4175 is a newly released bush snap bean {Phaseolus vulgaris L.) with resistance to root-knot incited by the nematode Meloidogyne incognita (Kofoid & White) Chitwood. B4175 is the first bush snap bean breeding line released with resistance to M. incognita derived from PI 165426 (2). The only cultivars available with M. incognita resistance are ‘Manoa Wonder’, a pole bean (3), and several pole types developed by the Alabama Agricultural Experiment Station (1). Use of resistant B4175 will broaden the genetic base of P. vulgaris lines with this character. Use of M. incognitaresistant cultivars will augment existing nematode control methods and is a feasible alternative to chemical control of nematodes.