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- Author or Editor: E. C. Tigchelaar x
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.
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).
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.
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.
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.
Abstract
Induced resistance to verticillium wilt occurs in fusarium-resistant tomato cultivars from dip inoculation with mixed cultures of Race 1 of Fusarium oxysporum f. lycopersici (F) and Verticillium albo-atrum (V). This induced resistance decreases as F level in mixed inoculi is reduced. Simultaneous screening for resistance to V and F can be achieved by inoculation with V and reinoculating 48 to 72 hours later with F.
Abstract
Pectinesterase (PE), polygalacturonase (PG), and cellulase (Cx form) activities and softening of 4 physiological maturities were compared in normal and rin tomatoes (Lycopersicon esculentum Mil cv. Rutgers). PG, PE, and Cx-cellulase activities increased during ripening of normal fruits. In rin fruits, PG activity was not detected, PE activity remained relatively constant, and Cxcellulase activity increased during ripening. The lack of softening in rin fruits appears to be associated with the lack of PG activity.
Abstract
Computer simulation was used to compare breeding progress under self fertilization with pedigree or mass selection, single seed descent (SSD) and combinations of early generation pedigree or mass selection with SSD. Pedigree selection was the most effective selection method at high (75%) and moderate (50%) heritabilities. At low (25%) and very low (10%) heritabilities, mass selection and SSD respectively yielded the best single F6 line. Early generation pedigree selection to F4 followed by SSD was not significantly different from pedigree selection alone at all heritabilities simulated.
SSD offers greatest benefits in situations where simultaneous selection is required for several characteristics under different heritabilities. SSD alone or in combination with mass selection retained greater genetic variability for line selection in F6. Pedigree or mass selection for highly heritable characters in early generations (F2 and F3) followed by SSD and F6 selection on the basis of line performance for characters of low heritability would appear to maximize progress for most breeding situations.