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- Author or Editor: James R. Baggett x
Abstract
Summer squash cultivars (Cucurbita pepo L.) of the Zucchini type were classified on a scale of 1 (open) to 5 (dense growth habit). A trial with 5 cultivars indicated that yield is not dependent on heavy foliage, and that picking time required per unit of crop is much less with open growth habit.
An inheritance study was inconclusive because of problems in progeny plant classification. It appears that growth habit is a complex of several characteristics, and as such, is inherited in a multigenic manner.
Incidence of head smut [Sphacelotheca reiliana (Kuhn) Clinton] in F corn (Zea mays L.) families derived from homozygous starchy (Su) F ears was less than that observed in starchy or sugary (su) families derived from segregating ears or sugary families derived from homozygous sugary ears. This difference was observed at high levels of disease incidence resulting from clipping seedlings and at a lower disease incidence in unclipped plants. Differences in seedling vigor and earliness of starchy and sugary families and differences related to homozygous and heterozygous sources suggest that seedling vigor may be involved in the observed differences in head smut susceptibility.
Pod detachment characteristics were studied in `EZ Pick', an unusually easy-picking cultivar, and `OREGON 91G', a normal cultivar. When `EZ Pick' pods were harvested by hand or by machine, they tended to separate at the pedicel-stem juncture or at the pedicel-calyx juncture, while `OREGON 91G' pods tended to break at the neck. When machine-harvested,'EZ Pick' had fewer broken pods, a higher recovery rate, and more trash than did `OREGON 91G'.
The inheritance in corn (Zea mays L.) of resistance to head smut disease incited by Sphacelotheca reiliana (Kuhn) Clinton was studied in the field on crosses of resistant dent corn line N6 with two susceptible sweet corn (su1) inbred lines. Disease incidence in the resistant parent (Pr) was 0% to 4%, and 83% to 96% in the susceptible parent (Ps). Predisposition of seedlings by clipping just above ground level increased percent infected in progeny populations by as much as 4-fold, but did not affect disease incidence in the, parents. At the lower disease incidence of unclipped plots, the F1, F2, and BCr means were close to the mean of Pr, suggesting dominance of resistance. At the high disease incidence of clipped plots, the relationship of parent and progeny means “suggested additive inheritance. Epistasis was also generally present with a higher level indicated for unclipped plots. Inheritance was concluded to be quantitative. Reciprocal differences were observed only in backcrosses. In the F2 and BCs populations, plants grown from dent (Su1) seed were lower in disease incidence than plants grown from su1 seed.
Abstract
‘Marbles’ and ‘Riot’ are dwarf peppers (Capsicum annuum L.) developed at Corvallis, Ore. on the research farms of the Oregon Agricultural Experiment Station. They bear prolific crops of attractive, brightly colored fruit on a compact plant, and are suitable for culture as bedding plants to provide fall color in the landscape.
The inheritance of tolerance to infection by bean leaf roll luteovirus (BLRV) in Pisum sativum L. was studied in the cross of cv. Parlay (sensitive to BLRV infection) × cv. Oregon Sugarpod II (BLRV tolerant). The parents, reciprocal F1, back-crosses, F2, and 234 random F3 families were screened in 1986 and 1987 in the field at Twin Falls, Idaho, under natural BLRV inoculation by aphids. Overall disease index scores for the F1, F2, and F3 were about intermediate between indices of the parents, with the F1 usually slightly higher than midparent values. Backcross disease indices were intermediate between the F1 and the respective parent involved. Distribution of individual F3 family indices was continuous and semi-normal. BLRV-sensitivity ranges within parents and selected cultivars, as well as segregating populations showed continuous variation and differed between the 2 years, suggesting that expression of a major gene was significantly influenced by natural variation in BLRV inoculation pressure and timing. An apparent “additive gene action” was probably an artifact of nonuniform timing and levels of infection within plant populations. Chi-square analyses of segregating populations indicated that a major recessive gene, called lrv, conferred BLR disease tolerance.