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Abstract
Lettuce (Lactuca sativa L.) cvs. Domineer and Grand Rapids were grown in the greenhouse at 4 soil moisture levels using 2 irrigation methods. Tipburn developed on immature ‘Domineer’ plants but not on ‘Grand Rapids’ in the high soil moisture beds 63 days after transplanting. Tipburn was observed on both cultivars when harvested at maturity 93 days after transplanting. Mature plants of ‘Domineer’ were more severely tipburned than those of ‘Grand Rapids.’
Edgeburn was first observed 53 days after transplanting on both cultivars at all soil moisture levels as pinpoint necrosis on outer leaves where the veins terminate at the leaf edge. The affected area enlarged with time and appeared to be associated with high levels of Mn.
Yields were higher at the 0.0–0.2 and 0.4 bar tension levels than at 2.0 bars. ‘Domineer’ gave higher yields than ‘Grand Rapids.’
Abstract
Chinese cabbage (Brassica campestris L. ssp. pekinensis) transplants grown under a protective, wax-coated paper cover were subjected to various degrees of defoliation (0%, 25%, and 50% of the foliar length) to determine the effect on the incidence of premature bolting and transplant shock recovery. Various transplant sizes (3–4, 5–6, and 7–8 true leaves) were used to determine differences in vernalization sensitivity and bolting ability. Protective tunnels significantly reduced the percentage of bolters. Olders transplants (7–8 leaves) without protection were superior in preventing bolting. The 5–6 transplants grown under tunnels produced the best overall yield. Partial defoliation failed to show consistent results on all parameters measured from year to year and from soil to soil.
Abstract
Interspecific hybrids between Solanum melongena L. cv. Millionaire and S. torvum Sw. were produced by hybridization using S. torvum as the pollen parent. The progeny was determined to be hybrid based on morphological and cytological observations. Reciprocal attempts to self- and backcross the hybrid to the parental species were unsuccessful. Observations of the pollen from the F1 plants indicated low viability. Meiosis in the parents appeared normal. Cytological observations of hybrid pollen mother cells (PMC) indicated abnormalities at all meiotic stages.
Abstract
Segregation for the difference in bolting response from a cross of Chinese cabbage (Brassica campestris L. ssp. pekinensis) and turnip (B. campestris L. ssp. rapifera) suggested that bolting was conditioned by 2 major additive genes. The chromosomal genome of the parents also appeared to effect segregation for this character. There was an apparent association between strong bolting resistance and turnip phenotype.
Abstract
Estimates of heritability and general and specific combining ability for resistance of tomato to Corynebacterium michiganense (E. F. Sm.) H. L. Jens, were made, using a half diallel with 6 parental entries. Both the general and the specific combining abilities of the parents differed. Additive variation accounted for 74% (narrow sense heritability) of the total variation, suggesting that a large part of the observed variation is fixable in true-breeding strains.
Abstract
Raised bed culture and different population densities were studied to determine their effect on bacterial soft rot (Erwinia carotovora ssp. carotovora) during summer production of Chinese cabbage (Brassica campestris L. Group pekinensis). Seeds were sown on different dates to determine the relationship between head formation and the occurrence of soft rot. Tropical (heat-tolerant) cultivars were evaluated for summer production potential in raised-bed and flat-culture systems. Raised beds were, in some instances, beneficial in reducing the incidence and progression of soft rot. Phyllosphere air temperatures on raised beds were slightly lower than on flat culture; however, the effect on reducing soft rot incidence is unclear. Plants grown at 30-cm within-row spacing produced fewer marketable heads than plants at 46, 61, or 76 cm. Plants from seed sown after mid June had a significantly higher incidence of soft rot when compared to earlier planting dates.
Abstract
The development of a jointless, Fusarium resistant tomato strain was complicated by a gametophytic factor. The backcross was made using the F1 as the female parent with the recessive parent as the male to eliminate competition. The backcross population was screened for Fusarium resistance. Survivors were selected for the jointless character and selfed to obtain progenies to test for Fusarium resistance. One plant family showing the predicted 4:1 ratio was recovered but no plant family showing the predicted 3:1 ratio was recovered.
Abstract
A comparison of inheritance patterns and heritability estimates from a NCII crossing model which included green and red cabbage, Brassica oleracea L. Capitata group, indicated differences between green × green and red × green crosses. Green × green crosses exhibited dominance for few non-wrapper leaves, greater efficiency index, and smaller leaf size while red × green crosses showed the opposite dominance pattern.
Abstract
A comparison of inheritance patterns and heritability estimates from a NCII crossing model which included green and red cabbage, Brassica oleracea L. (Capitata group) indicated differences between green × green and red × green crosses. Green × green crosses exhibit dominance for early maturity, large head weight, small non-wrapper leaf weight and small stalk weight while red × green crosses exhibit the opposite dominance pattern.
Abstract
Fruit detachment force (FDF) in pepper (Capsicum annuum L.) was measured using mature fruit for the parental, F1, and F2 populations from the cross MSU 160 × MSU 249. Fruit detachment force was controlled by a low number of effective factors (k = 1-2) behaving mainly in an additive manner. Correlation coefficients between fruit detachment force and fruit length, width, and weight calculated from F2 data were positive and significant at the 1% level.