Abstract
‘Pennfresh ADX’ is a high-sugar sweet corn hybrid (Zea mays L.) based on the recessive endosperm gene combination amylose-extender (ae) dull (du) waxy (wx). The effects of this gene interaction on starch and sugar properties were reported by Creech (1). This hybrid can be harvested over a longer period than traditional sweet corns which are homozygous for the sugary (su) gene, and it retains its quality much longer following harvest. The symbol ADX is derived from these 3 gene names and is used to delineate this new class of sweet corn hybrids.
Abstract
‘Dokodoko’ is a new watermelon (citrullus lanatus (Thunb.) Matsum. & Nakai) selected for its adaptation to the humid tropics with close to 10% soluble solids. The name ‘Dokodoko’ in Ghanian means very sweet.
Abstract
Forty-five plants of sweet potato (Ipomoea batatas (L.) Lam.) taken randomly from the second cycle of a mass-selection population, and 25 open-pollinated progeny from each were used to estimate heritabilities (h2) of 7 root traits: root weight, 0.25 ± 0.13; intercellular space (IS), 0.70 ± 0.14; percent of dry matter (DM), 0.65 ± 0.12; sprouting, 0.39 ± 0.14; flesh oxidation, 0.24 ± 0.13; flesh color, 0.53 ± 0.14; and cortex thickness, 0.25 ± 0.13. IS was distributed normally with mean and mode of about 7%. DM had a bimodal distribution with mean 28.8 and modes of 27 and 31%. At least 2 genetic systems were apparently involved in expression of DM; one was associated with orange flesh and the other, with white flesh. This is the first report of the h2 for IS, DM, and sprouting.
Abstract
Colored and white seeded inbred bean lines resistant to mechanical damage (MD) and transverse cotyledon cracking (TVC) were crossed with 2 susceptible white seeded snap bean cultivars. Resistance to both MD and TVC was inherited quantitatively although colored segregants were more resistant than white-seeded segregants, MD and TVC resistant white-seeded selections were obtained. Broad-sense heritability varied from 55 to 79% for MD and 53 to 93% for TVC; narrow-sense heritability resistance varied from 22 to 73% for MD and from 22 to 58% for TVC. Severe selection pressure for MD resistance on bulked F3 seed was shown to be a simple and practical method to obtain resistance.
Abstract
A parent-offspring test of 21 sweet potatoes (Ipomoea batatas (L.) Lam.) and 25 open-pollinated offspring from each provided heritability estimates (h2 ± SE) for root fiber (0.47 ± 0.04), weight (0.41 ± 0.04, shape (0.50 ± 0.05), cracking (0.37 ± 0.04), and sprouting (0.37 ± 0.02). These characters were sufficiently independent to allow selection of one, or of any combination simultaneously, without adverse effects on the others.
Abstract
Immature white seedcoat (IW), consisting of reduced green color in immature seedcoats and early development of white color in white seeded cultivars of Phaseolus vulgaris, is described. IW was found in 9 of 66 commercial cultivars. It occurs irrespective of mature seedcoat colors, pod pigmentation, or wax vs. green pod color. Genetic analyses of progenies from 6 crosses indicated IW is conditioned by a single recessive gene which is not linked with the P locus for mature seedcoat color or with Y for green vs. wax pod. The gene designation iw is proposed for immature white seedcoat.
Broccoli (Brassica oleracea L. Italica Group) lines with heads borne above the foliage (exserted) favorably for mechanical harvest were crossed with inbred lines with nonexserted heads. Length of the heads, defined as the portion of the plant above the highest major leaf, was ≈50% of the total plant height in short and tall parents and all plants of the F1, F2, and backcross generations. The principal characteristic identified with good head exsertion was long internodes. Internode length was inherited mostly in an additive manner, with some effect of hybrid vigor apparent in the F1, F2, and backcross to the tall parent. Plant height was also inherited in an additive manner. Head weight in the high-exsertion parent was much lower than in the low-exsertion parent. Within each parent and the F1, head weight was greater in plants with longer internodes and greater plant height. In the segregating generations (F2 and backcross), head weight increased with decreasing internode length, indicating that selection for high head exsertion would result in smaller heads and reduced yield.