‘TAMU Triple Cross’ is a three-way hybrid pickling cucumber (Cucumis sativus L.) developed for mechanical harvesting. It is the first American pickling-type hybrid cucumber developed from three inbreds. ‘TAMU Triple Cross’ exhibits several outstanding characteristics including high yield, desirable fruit shape, dark green color, excellent processing qualities both as brinestock and fresh pack, broad spectrum resistance to cucumber diseases, and finally, an improved and less expensive system for production of hybrid seed (1,2,3).
A field study was conducted on TG1015Y onions (Allium cepa L.) grown in the Lower Rio Grande Valley of Texas. Treatments included two soil types (clay & loam), four harvest dates throughout the bulbing process, and two S rates [0 kg S/ha (standard) & 22.4 kg S/ha (high)]. Laboratory analysis included pyruvic acid concentration for pungency measurement, percent dry matter, and sucrose, glucose, and fructose concentrations. Harvest date influenced all variables tested. Percent dry matter generally decreased as bulbs matured (8.0 to 6.9% DM) with a slight increase at maturity (7.4% DM). Enzymatically developed pyruvic acid concentrations ranged from 3.13 to 4.03 μmole/g fresh wt. There was an upward trend of pyruvic acid over the bulbing process. Total sugars, measured by HPLC methods, tended to increase during bulb development (39.3 to 46.5 mg/g fresh wt.). However, sucrose decreased during the last two harvests causing a corresponding increase in glucose and fructose. The S treatment had no effect on any of the factors measured. The only influence by soil type was sugar concentration, with the loam field being higher in glucose.
An `intermediate leaf' hybrid pickling cucumber (TAMU 884304 X ARK H-19 `little leaf') was direct-seeded at four plant densities (94,570; 48,440; 32,290; 25,375 plants/ha) using four within-row spacings (15, 30, 45, 60cm) at two locations and two seasons. Optimum yield based on marketable fruit number, grade distribution and fruit quality occurred with 94,570 plants/ha. Optimum harvest time depended on location and season. Delayed harvest times were also evaluated. Harvests with fruit >5.1cm in diameter had severely reduced brining quality. Fruit did not enlarge or enlarged slowly to oversize. This resulted in a mixture of fruit ages within the largest marketable fruit grades. It is recommended that `little leaf' lines and their hybrids such as `intermediate leaf' be harvested when fruit 3.8 to 5.1cm in diameter appear and before oversize fruit are produced. Spacing did not significantly effect length/diameter ratio(LDR) but LDR was significantly greater for delayed harvests.
Microscopic observations revealed that the epidermal layer of fruit of MSU 35G (warty) was composed of cells whose longest axis were perpendicular to the fruit surface and about 50 µ thick. The epidermal layer of fruit of MSU 6902 (non-warty) was composed of cells approximately 20 µ thick with little elongation in either visible axis. The F1 (warty) and warty fruit in the F2 exhibited a cellular shape similar to the warty parent. However, the thickness of epidermal cells of these warty progency were significantly less than that of the warty parent when observed in cross-section. Epidermal cell thickness of warty fruit observed in cross-section became increasingly less as the percentage of MSU 6902 in the genetic background increased. Subepidermal cells of fruit with non-warty skin were larger than corresponding cells of warty fruit. The epidermal cell shape of MSU 6902 was linked with the non-warty characteristic. Epidermal cell thickness is inherited independently of epidermal cell shape.
A true hermaphrodite cucumber was derived from the andromonoecious cultivar ‘Crystal Apple’. Hybrids developed by using gynoecious lines and the hermaphrodite line, TAMU 950, were 100% gynoecious. Fruits produced on the hybrids were similar in size and shape to that of the gynoecious parent. Use of the hermaphrodite in the production of such totally gynoecious hybrids permits the blending of precise quantities of a monoecious pollinator with hybrid seed before planting. Production of 100% gynoecious hybrids in this manner make parthenocarpic hybrids feasible.
Two gynoecious inbred lines of cucumber, ‘Gy 3’ and ‘MSU 35G’ their hybrids with the hermaphroditic ‘TAMU 950’ and backcrosses of the hybrids to their respective gynoecious parents were treated with gibberellin to test the phenotypic stability of gynoecism. Hybridization with ‘TAMU 950’ stabilized the gynoecious character and gibberellin A4/A7 provided a good test of stability.
Germination and radicle elongation experiments were performed with six cultivars of cucumber (Cucumis sativus L.) at seven salinity concentrations (0, 0.8, 4.0, 6.0, 9.0, 12, and 15 dS·m−1). Increasing salinity has no effect on final germination percentage after 5 days, but did decrease radicle elongation. In seedling growth studies with salinity levels ranging from 0.8 to 12 dS·m−1, increasing salt levels decreased shoot length and shoot dry weight. Analysis of shoot tissue from these seedlings indicated that higher salinity levels increased concentrations of Ca and Na, while Mg and K concentrations decreased. Yield and fruit quality were measured in a greenhouse study at two salinity levels (1.6 and 4.0 dS· m−1). Salinity significantly decreased fruit yield in five of six cultivars, but had no effect on fruit quality. Seedling shoot length of a cultivar grown at 9.0 dS· m−1 was correlated with relative yield at 4.0 dS· m−1. A salinity screening technique based on this relationship is proposed.
A new designer carrot, `BetaSweet', with high levels of anthocyanin, betacarotene, and crispy texture was developed by the Vegetable Improvement Center at Texas A&M Univ. The new carrot contained low levels of low-volatile terpenoids, responsible for the harsh flavor in carrots and high levels of reducing sugars. Carotenoid content increased with carrot maturity and stabilize at 120 days after sowing for orange and maroon genotypes; however, the maroon genotype was 35% higher than the orange cultivar. Anthocyanin, a cancer preventive compound and not detected in ordinary orange carrots, is present in `BetaSweet' maroon carrot with 89.8 mg·100 g-1 of fresh weight. High percentage of soluble solids and succulence in the maroon cultivar seemed to contribute to the favored sweetness perception by consumers. A consumer taste panel showed a significant difference between orange and maroon genotype for sweetness, texture, and overall carrot flavor.
Poor and inconsistent germination is a problem in triploid watermelon. Nicking was shown effective in improving germination in triploid cultivars. In this experiment, we examined the effects of high and low medium moisture, and nicking on diploid and triploid seed germination. Germination for the diploid cultivar was unaffected by any treatment. At high moisture conditions, triploid seed germination was severely reduced to less than 15%, while nicking significantly improved germination up to 40%. However, this increase is still not commercially acceptable. When seed morphological components were measured for each cultivar, triploid seeds had a larger and highly variable air space as compared to the diploid seed. The data confirm that seed germination is not inhibited by the seedcoat alone, but appears to be highly sensitive to excessive water conditions.