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  • Author or Editor: James R. Baggett x
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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.

Open Access

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.

Free access

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.

Free access

In crosses between stringless and stringy podded pea cultivars, all plants of the F1 and backcross to the stringy parent had stringy pods. F2 ratios varied widely among crosses, and populations always had more stringy plants than expected, based on a single locus. The ratio of nonsegregating (stringy): segregating F3 families derived from stringy F2 plants fit a single-gene hypothesis in half of the crosses. Backcrosses of F1 to the stringless parent fit the expected 1:1 ratio when the pollen parent was stringless, but the reciprocal backcrosses showed a deficiency of stringless plants, suggesting that poor competitive ability of pollen bearing the stringless factor was the reason for deficiencies of stringless plants. It is concluded that stringlessness is controlled by a single recessive gene for which the designation sin-2 is proposed. A reduction in pod size, plant height, and number of wrinkled seed segregates was associated with stringlessness.

Free access

Abstract

The inheritance of internode length and plant height in bush forms of common bean (Phaseolus vulgaris L.) was studied in crosses of E6211, a bush bean of ‘Blue Lake’ type with elongated internodes, with three lines having a more compact growth habit. Apparent dominance of long internode expressed by the F1 and backcrosses of one cross, E6211 × K19, in both greenhouse and field, was not supported by the F2, which showed additive gene action. For both internode length and plant height, the trend was for slight dominance of either the tall or short parental type in the F1, with the F2 showing more additivity or greater dominance of the short parent than the F1 or backcrosses. Field results supported additive inheritance more than did greenhouse results.

Open Access

Abstract

The tendency for axillary head (AH) development in Brassica oleracea (Capitata group) was shown to be a heritable characteristic. In 11 crosses between high and low AH lines carried at least through the F2 generation, AH was recessive and largely controlled by one or a few genes. In other crosses, in which only the F1 generation was studied, AH tendency usually resembled that of the parent having a low level of AH, but in certain crosses was intermediate or closer to the high scoring parent. Expression of AH was continuous and apparently influenced by modifying genes and the environment. Broadsense heritability estimates were high, but narrowsense heritability estimates were very low indicating dominance effects. No consistent or apparently important differences were found between reciprocals. The weight of AH was not related to yield of main heads in F2 plants.

Open Access

Abstract

Oregon 11 is an extremely early tomato (Lycopersicon esculentum Mill.) of small to medium size that has a strong tendency for parthenocarpic fruit set under cool summer conditions. Oregon 11 flowers early and sets fruit under the cool conditions encountered in western Oregon. It was released for breeding purposes and trial in home gardens, where it may be useful in providing ripe fruit before larger, higher quality cultivars begin to ripen.

Open Access
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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.

Open Access