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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
‘Mainstream’ is a high yielding, small-fruited muskmelon (cantaloupe), Cucumis melo L. weigh 1.1-1.4 kg, have good keeping quality, a pleasing sweet taste, and are high in Vitamin C. The plants are compact and resistant to powdery mildew (Sphaerotheca fuliginea (Schlecht. ex Fr.) Poll.), downy mildew (Pseudoperonospora cubensis (Berk. & Curt.) Rostow., and cucumber beetles (Diabrotica undecimpunctata howardi Barber, Acalymma vittata (Fabricius), and Diabrotica balteata LeConte.
Abstract
Bush type snap beans (Phaseolus vulgaris L.) with resistance to the root-knot nematode, Meloidogyne incognita (cotton strain) are being developed by using PI-165426 as the resistant parent. PI-165426 (resistant), ‘Black Valentine’ (susceptible) and F5 breeding line B3864 (resistant) were inoculated with second-stage larvae. There were no significant differences in larval penetration of roots. Root tips showed slight swellings at infection loci of resistant and susceptible plants. Necrosis was evident in the resistant lines 4 days after inoculation. Histological studies of early infections showed that resistance was due to absence of adequate giant cell development and to hypersensitive reaction within the infected portion of the root. When soil temperature was changed from 16 to 28°C, galling, female development, and egg mass production in the resistant plants were increased.
Abstract
Paper chromatograms of flavonoid compounds extracted from the leaves of 43 snap bean cultivars and breeding lines produced characteristic patterns which allowed all but 7 to be classified into one of 3 major categories. One of the flavonoid compounds was consistently associated with bush and not runner type plants and was thus useful for early classification of populations segregating for plant type. The high degree of similarity among cultivars for a set of characters which one might expect to be distributed at random suggests a rather narrow gene base for this crop.
Abstract
In the early 1970s, a study was begun to find resistance to feeding in muskmelon, Cucumis melo L., by banded cucumber beetles, Diabrotica balteata LeConte. Bitter seedlings were observed to be more susceptible to feeding than nonbitter seedlings. We noticed reduced damage levels in both bitter and nonbitter seedlings in 1974. Genetic study of resistant materials showed that in addition to the recessive form of the bitter gene, bibi, a 2nd recessive gene, cbl cbl, conditioned reduced seedling susceptibility. Subsequent tests involving spotted (Diabrotica undecimpunctata howardi Barber), striped [Acalymma vittata (Fabricius)], and banded beetles on leaf disks of several C. melo cultivare showed that homozygous double recessive, bibi cblcbl, plants were more resistant to all 3 species of cucumber beetles than nonbitter, bibi Cbl — and bitter Bi—Cbl— plants. This double-recessive resistance provides muskmelon breeders with germplasm which can be incorporated into breeding lines and hybrids.
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
‘Green Ice’ is a green-fleshed muskmelon (Cucumis melo L.) adapted to the climatic conditions prevalent in the southeastern United States and is well-suited for both commercial and home garden production. It is a high-yielding ‘Honey Ball’-type muskmelon that produces round to oval, pale gray-green, medium-sized fruit that turn cream-colored and slip from the vine at maturity. The thick light-green flesh has a pleasing aroma and sweet flavor and is high in vitamin C. The vigorous plants are resistant to race 3 of powdery mildew [Spaerotheca fuliginea (Schlect ex Fr.) Poll.] and tolerant to most pests and environmental stresses of the region.
Abstract
The salt tolerance of cultivars of muskmelon (Cucumis melo, L.) was established under 2 levels of radiation in a glasshouse experiment. ‘Galia’ and ‘Top Mark’ muskmelon differed very little in salt tolerance at either radiation level. The maximum electrical conductivity of a saturated soil extract without yield reduction, the salt tolerance threshold, was 2.0 dS m−1. Beyond the threshold, yield was reduced at a rate of 14.3% per unit increase in soil salinity. Both cultivars were more salt-tolerant at the higher level of solar radiation.
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.