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- Author or Editor: Hanna Y. Hanna x
Black polyethylene mulch is preferred for producing early spring tomatoes (Lycopersicon esculentum Mill.) because of its warming effect on the soil around the roots. However, using the same mulch for double-cropping cucumbers (Cucumis sativus L.) with tomatoes is considered by some growers to be undesirable because of the belief that heat accumulation under the mulch in midsummer or early fall is detrimental to cucumber yield. Eight studies were conducted from July to September in 1994, 1995, and 1996 to determine the effects of mulching spring tomatoes with black vs. white polyethylene mulch on the growth and yield of subsequent cucumber crops. Soil temperature recorded after planting cucumbers ≈4:00 pm for 3 weeks was higher under black mulch than under white mulch. Color of the mulch did not affect leaf length, leaf width, and plant dry weight of cucumbers in six of the eight studies. Cucumbers grown on black mulch produced longer leaves in one study and wider leaves in two studies, and plant dry weight was lower in two studies. Mulch color had no significant effect on the premium or total yields of cucumbers in all but one study. Cucumbers grown on black mulch produced lower percentages of culls in two studies.
A study was conducted to determine if air blowers would be less time consuming, more economical, and as effective as hand-held electric vibrators to pollinate two greenhouse tomato (Lycopersicon esculentum) cultivars. Vibrator-pollinated plants of each cultivar produced greater marketable yield than did blower-pollinated plants. Within cultivars, marketable yield was greater and yields of culls were lower with vibrator-pollinated plants. Fruit weight and diameter and the number of seeds per fruit were greater in vibrator-pollinated plants. Marketable yield of `Trust' was greater and cull yield was lower than that of `Caruso' in 1996. However, marketable yield of `Caruso' was greater than that of `Trust' and cull yield was about the same in 1997. Interactions between pollinating tools and cultivar were not significant except for fruit weight in 1997. The time needed to pollinate 640 plants for 13 weeks was 7.13 and 11.75 person-hours using the air blower and the electric vibrator, respectively. Labor cost for pollination was $49.92 for the air blower and $82.25 for the vibrator. Yield loss using the air blower for pollination was not offset by the savings in operating costs.
Abstract
Fruit set of 6 genotypes of tomato (Lycopersicon esculentum Mill) ranged from 50% (BL6807) to l% (L401) in the summer and from 93% (BL6807) to 78% (L401) in the spring. Flower drop was significantly higher in the summer for each cultivar, except for BL 6807 where there was no difference. All genotypes had significantly more underdeveloped ovaries in the summer and generally less normal pollen, smaller fruit, and less seed per fruit. Although these variables were related to low fruit set at high temperatures, they were not primarily responsible for this character.
Abstract
Seven tomato genotypes (Lycopersicon esculentum Mill) were crossed in all except reciprocal combinations in a diallel test for heat tolerance. S6916 had the highest general combining ability (GCA) value for heat tolerance, indicating that it transmitted good fruit setting abilty at high temperatures to its progeny. BL6807 had the second highest GCA value for fruit set but also transmitted underdeveloped ovaries. L401 had the lowest GCA value for fruit set. Additive gene action was more important than nonadditive effects for fruit set, flower drop, and underdeveloped ovaries at high temperatures.
Seaweed extract has been reported to have various beneficial effects on many crops. A study was conducted in 1989 and 1990 to evaluate the effects of Response 9-9-7, a seaweed extract fortified with NPK, on yield of staked tomatoes and cucumbers. Plants were sprayed to the runoff weekly, biweekly, every 3 weeks and every 4 weeks with 1:500, 1:250, 1:150 and 1:125 v/v Response/water respectively. Results indicate that spring tomatoes sprayed with Response 9-9-7 at all rates outyielded the check which was sprayed with plain water. However, the only significant difference was obtained when tomatoes were sprayed with 1:150 Response/water in 1989 and 1:500 in 1990. Response/water at 1:500 rate significantly increased the quality and marketable yield of cucumber in both years. Response 9-9-7 had no effect on yield of tomatoes grown in the summer under heat stress.
Apple scab, caused by Venturia inaequalis (Cke.) Wint., is the most serious disease of apple trees. Resistance to V. inaequalis, derived from the small-fruited species Malus floribunda 821, is determined by a major dominant gene Vf. Our major objective is to identify RAPD markers linked to the Vf gene. The approach in this paper is based on the introgression of the Vf gene from M. floribunda into commercial cultivars. Almost 200 random sequence decamer-primers have been used to screen a pair of bulked samples and the donor parent M. floribunda clone 821 for markers linked to the Vf gene conferring resistance to apple scab. A single primer has been identified which generated a PCR fragment, OPK16/1300, from the donor parent M. floribunda clone 821 and the scab-resistant selections/cultivars bulk, but not from the scab-susceptible recurrent parent bulk. Co-segregation analysis using a segregating apple progeny and polymorphism analysis of individual scab-resistant Coop selections/cultivars have confirmed that this marker is linked to the scab-resistance gene Vf. OPK16/1300 has since been cloned and sequenced. Sequence-specific primers of 25 oligonucleotides based on the marker have been synthesized and used to screen further M. floribunda clone 821, scab-susceptible apple cultivars, scab-resistant apple cultivars, and scab-resistant Coop selections. The sequence-specific primers have identified polymorphisms of OPK16/1300 based on the presence or absence of a single band.
Almost 200 random sequence decamer primers were used to screen a pair of bulked samples of apple (Malus ×domestica Borkh.) DNA and that of the donor parent Malus floribunda Sieb. clone 821 for molecular markers linked to the Vf gene conferring resistance to apple scab [Venturia inaequalis (Cke.) Wint.]. Identified was a single primer that generated a polymerase chain-reaction (PCR) fragment, OPAR4/1400, from the donor parent M. floribunda clone 821 and the scab-resistant selections/cultivars bulk, but not from the scab-susceptible recurrent-parent bulk. Cosegregation analysis using a segregating apple progeny and polymorphism analysis of individual scab-resistant selections/cultivars confirmed that this marker was linked to the scab-resistance gene Vf OPAR4/1400 was then cloned and sequenced. Sequence-specific primers of 25 oligonucleotides based on the marker were developed and used to screen further M. floribunda clone 821, scab-susceptible apple cultivars, scab-resistant apple cultivars, and scab-resistant Purdue, Rutgers, and Univ. of Illinois apple breeding program selections. The sequence-specific primers identified polymorphisms of OPAR4/1400 based on the presence or absence of a single band. This molecular marker is at a distance of about 3.6 cM from the Vf gene.
Abstract
In field experiments conducted during 2 years, substantial yield increases were obtained with vertically trained (staked) cucumber plants (Cucumis sativus L.) over vining plants (unstaked). The marketable yield was doubled in some instances, and fruit rot was reduced significantly. More female flowers set and developed into marketable fruits on vertically trained plants than on vining plants. The fresh weight, length, and width of the leaves on the main stem of the staked plants prior to the first harvest were also greater than on unstaked plants. The staked plant fresh weight prior to the first harvest and after the last harvest was significantly greater than that of unstaked plants, but both had the same number of female flowers. Reducing within- row plant spacing from 30 to 15 cm significantly increased yield. Weekly foliar fertilization with 1.5N-0.4P-0.6K (kg·ha−1) for 8 weeks did not increase yield.
Abstract
In the article “Increased Yield in Slicing Cucumbers with Vertical Training of Plants and Reduced Plant Spacing”, by H.Y. Hanna, A.J. Adams, and R.N. Story (HortScience 22:32–34, April 1987), in Table 1, the significance of G8M in 1983 should be at the 5% level by F test. The correct table in printed below.