Search Results

Abstract

The effects of 5-methyl-7-chloro-4-ethoxycarbonylmethoxy-2, 1, 3-benzothiadiazole (MCEB), a proposed inhibitor of ethylene action, and (2-chloroethyl) phosphonic acid (ethephon) on sex expression were observed in androecious and gynoecious phenotypes of cucumber (Cucumis sativus L.) under greenhouse conditions. MCEB had no effect on the androecious phenotype while ethephon (50 ppm) induced pistillate flowers. The effect of MCEB and ethephon treatment was a marked reduction in the number of ethylene-induced pistillate flowers except when there was a 48-hour period between applications of ethephon and MCEB. In the gynoecious phenotype, MCEB (75 ppm) induced staminate flowers, ethephon had no effect, and the effect of MCEB and ethephon treatment was to induce staminate flowers at relatively high concentrations of MCEB (150 ppm).

Abstract

Calcium (Ca) level of leaves sampled in mid- or late summer was closely related to peel Ca levels of mature apples (Malus pumila Mill. cv. Baldwin). Ca content of fruit was directly related to fruit yield of the tree, cycling with biennial bearing. In 1971 bitter pit incidence could be predicted from either leaf or peel Ca; internal breakdown and decay were less predictable. In 1972 leaf Ca and peel Ca averaged, respectively, 27 and 17% higher than in 1971, accompanying increased yield. Little bitter pit, internal breakdown, or decay occurred, even at Ca levels correlated with high incidence rates the previous year. We concluded that Ca must be only 1 among several factors regulating these occurrences.

Abstract

Postclimacteric respiration of apples (Malus pumila Mill. cv. Baldwin) decreased as peel Ca level increased from 400 to 1300 ppm. The respiratory climacteric occurred simultaneously in fruit of all Ca levels, indicating that maturation was unaffected by these Ca levels. Occurrence of bitter pit was inversely related to Ca levels. Scald, internal breakdown, and decay were more prevalent when peel Ca was below 700 ppm. Fruits were firmer after 5 months storage in 0°C air if Ca was below 700 ppm, although they were larger, yellower, and more susceptible to decay and other disorders than higher Ca fruit.

Abstract

Ethephon applied as a foliar spray caused an androecious (all-male) line of Cucumis sativus L. to produce pistillate flowers analogous to those of monoecious phenotypes. The degree of conversion depended on the concentration of ethephon and stage of growth at the time of application. In the greenhouse, a concentration of 50 ppm applied at the 3- or 4-leaf stage was the best treatment for induction of pistillate flowers without marked inhibition of growth.

Abstract

Parthenocarpic fruiting of genetically parthenocarpic and non-parthenocarpic pickling cucumber lines was determined under different thermo-photoperiods. The genetically parthenocarpic line, MSU 364G, produced both earlier and more fruits under all thermo-photoperiod treatments than the genetically non-parthenocarpic line, Gy 3. This was especially true at high night temperatures (18°C). Thus, maximum selection pressure for yield in genetically parthenocarpic lines might be best exerted under high night temperatures. Conversely, the production or yield of parthenocarpic fruits was greatest under low night tempeartures (12°C). Hybrids involving either of these 2 parental lines and 2 hermaphroditic lines were intermediate for parthenocarpic yield. Yield of parthenocarpic lines was associated with intensity of femaleness, i.e., strong femaleness resulted in earlier fruiting and greater numbers of parthenocarpic fruits. The development of parthenocarpic pickling cucumber cultivars for once-over mechanical harvest seems practical by combining parthenocarpic with gynoecious genotypes.

Abstract

The response to surface placement of Nitrogen and Potassium fertilizer materials at: 1) dripline, 2) inside and 3) broadcast was observed for 5 years. Inside placement of equal or lesser amounts of fertilizer was as effective, and at times more effective, than dripline or broadcast placement. It appears possible that herbicides and fertilizer may be applied close to the bole of the tree in a single operation.

Abstract

Hydrated dolomitic limestone as a slurry was injected under pressure to soil depths of 3 feet under apple trees growing in acid loamy sand soil. Comparisons of: 1) dripline vs. near bole placement, 2) spring vs. fall application and 3) trees having high leaf magnesium vs. trees having lower leaf magnesium were made. Near bole treatment appeared superior to dripline placement; the response of trees to spring applications were immediate, exceeding the response to fall application, and trees having a higher original leaf magnesium content were more responsive than those of lower leaf magnesium.

Abstract

The influence of Mailing (M)26, M9, M27 rootstocks and stempiece/rootstock combinations M9/Malling-Merton (MM)106, M9/MM111, M27/MM106, and M27/MM111 on growth, leaf nutrition, and fruit quality of ‘Empire’ apples (Malus domestica Borkh.) was evaluated. After 8 growing seasons, height and spread of trees on M26, M9/MM106, M9/MM11, M27/MM106, and M27/MM111 were similiar and were greater than those of trees on M9 and M27. Mn concentration in leaves from trees on M27 was higher than that of leaves from trees on other rootstock and stempiece/rootstock combinations. Production of trees on M26, M9/MM106, and M27/MM106 was greater than that on M9/MM111, M9, and M27. When fruitfulness was related to trunk area, trees on the various rootstock and stempiece/rootstock combinations did not differ in production efficiency. Effect of rootstock or stempiece/rootstock on fruit size was inconsistent. Fruit from trees on M27/MM111 entered in to their climacteric later than those from trees on M26 and M 27 for 2 years and from trees on M9 and M9/MM106 for 1 year, but the delay was small. No fruit flesh firmness differences were detectable. Soluble solids content of fruit from trees on M27 was higher than that of fruit on M26, M9/MM111, and M27/MM111. Senescent breakdown was more prevelant in fruit from trees on M26 than on M9, M27, M9/MM111, and M27/MM111.

Abstract

Effects of 4 daylength and temperature combinations on sex expression and growth of androecious (allmale) cucumber (Cucumis sativus L.) were studied. Three of 4 androecious lines were stable for male expression under all 4 combinations. However, low temperature and short days promoted femaleness in one line causing monoecious expression.

Ethylene production by androecious was compared to that of monoecious, andromonoecious, hermaphroditic and gynoecious phenotypes. Low ethylene evolution was associated with plants of androecious and monoecious phenotypes as compared to more female phenotypes. Furthermore, ethylene production by androecious plants remained low and constant throughout 30 days of growth, but a small peak in ethylene production by monoecious plants was noted. This small peak may be associated with the initiation of female flowers in monoecious phenotypes.

Abstract

Three different methods of sampling flesh of apple (Malus domestica Borkh.) for Ca analysis produced different results due to uneven Ca distribution in the fruit. A sensitive, reproducible method of sampling and analyzing the outer cortex of the calyx half of fruits indicated that Ca concentration in different parts of the fruit changed significantly after harvest, decreasing in the core and increasing in the outer cortical tissues. Massive applications of CaCl₂ to trees shortly before harvest increased flesh Ca concentrations and red coloration of the fruit, decreased flesh softening during storage and senescent breakdown after storage, but caused significant injury to the fruit.