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  • Author or Editor: E. C. Tigchelaar x
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Abstract

The dictionary defines ripening as “the aging (or curing) process to develop characteristic flavor, odor, body, texture and color.” The plant physiologist identifies ripening as the terminal period of maturation during which the fruit attains its full development and its maximum esthetic and edible quality (1).

Open Access

Abstract

Twenty-one prior lists of new vegetable varieties introduced since 1936 have been published by the American Society for Horticultural Science. This 22nd listing includes 434 cultivars introduced in the past few years.

Open Access

Abstract

Seed germination at 10°C in partially isogenic F5 lines of tomato (Lycopersicon esculentum Mill.) with varying low-temperature germinating abilities was negatively correlated with oleic acid levels and positively correlated with linoleic acid contents. Fatty acid composition did not change with time of incubation at 10°C, nor in the presence of activated carbon. Fatty acid composition of membrane-lipid fractions was similar to the total fatty acid of the seeds. The proportion by which linoleic acid is higher in cold-germinating lines (CG) is roughly the same as the amount by which oleic acid is lower in non-cold-germinating (NCG) lines. We suggest that gene regulation of cold-germinating ability is associated with a more extensive desaturation of oleic acid into linoleic acid during seed development.

Open Access

Abstract

The importance of good quality, highly vigorous seed for agricultural production of crop plants cannot be overemphasized. With the ever increasing demands for a mechanized, energy-efficient type of agriculture, we have come to the stage where one plant is expected for every seed sown. Moreover, modern agriculture demands that each emerging plant grow and develop uniformly under a wide range of environmental conditions. The recent development of precision seeding equipment for small-seeded crops, improvements in chemical weed control, and the need for high plant populations and uniform plant stands for machine harvest has led to a growing interest in direct field seeding.

Open Access

Abstract

The inheritance of low temperature seed sprouting ability in tomato (Lycopersicon esculentum Mill.) was found to be polygenic with dominance for inability to germinate at suboptimal temperatures. A minimum of 3 genes is suggested from F2 data and a minimum of 5 genes from backcross results. Broad sense heritability was estimated at 97%; narrow sense heritability, at 66%.

Genes controlling determinate, brachytic, and dwarf habits of growth had no significant effect upon subsequent low temperature sprouting response in the F2 generation. Significant differences in ability to germinate at low temperatures were found among reciprocal F1’s.

Open Access

Abstract

‘Caro-Rich’, an indeterminate high pro-Vitamin A tomato (Lycopersicon esculentum Mill.), was released in January 1973. It was named for its high β-carotene.

Open Access

Abstract

Changes in respiration, ethylene production, firmness, pectolytic enzyme activity and carotenoid accumulation during ripening were monitored in fruit of a segregating population of the non-ripening (nor) mutant of tomato (Lycopersicon esculentum Mill.). In fruit from mutant (nor/nor) plants, no respiratory or ethylene climacteric was observed, firmness declined very slowly with only trace levels of polygalacturonase present in mature fruit and phytoene, β-carotene and neurosporene were the major carotenes. In very old fruit (120 days’ post-anthesis), lycopene and β-carotene were the predominant carotenoids, however lycopene content was less than 10% of normal.

Ripening of fruit from heterozygous (nor+/nor) plants was delayed and occurred more slowly than for normal (nor+/nor+ ) fruit. The respiratory climacteric was partially suppressed, peak ethylene production was one-sixth of normal, fruit softening was retarded, and polygalacturonase activity was lower at comparable maturity stages. Fruit from heterozygous (nor+nor) plants accumulated lycopene, gamma-carotene, phytofluene, and phytoene at a slower rate, but β-carotene accumulation was similar to normal. A mechanism for action of nor in control of ripening is proposed.

Open Access
Authors:
the Garden Seed Research Committee, American Seed Trade Association the Garden Seed Research Committee, American Seed Trade Association
and

Abstract

Twenty prior lists of new vegetable varieties introduced since 1936 have been published by the American Society for Horticultural Science. The most current listing was published in 1975 and more than 500 new vegetable varieties have been introduced in the past five years. This 21st Listing includes 407 cultivars introduced within the past decade. A 22nd Listing will be published in 1981 to bring lists up to date. In view of the large numbers of new introductions appearing each year, attempts will be made to publish future listings annually in HortScience.

Open Access