Search Results
Abstract
The relationships between photosynthetic rate, yield, and yield components of forcing tomatoes (Lycopersicon esculentum Mill., cvs. Tuckcross V and Tuckcross 533) under variable lighting and spacing were studied during the dark winter of 1972-73. Yield and its components were all highly and positively correlated with both cloudy-day (90-110 W/m2 light intensity) and sunny-day (200 W/m2 or higher) photosynthetic rates. The rate-yield relationship remained nearly constant irrespective of the predictor variable. Better linear response of yield and its components to cloudy than to sunny-day photosynthetic rate was observed. Photosynthetic rate accounted for more than 60% of the yield variation.
Abstract
A 6-parent diallel was used to investigate the relationship between blossom-end rot (BER) and the uniform-ripe fruiting trait of tomato (Lycopersicon esculentum Mill.). Three parents possessed the uniform-ripe character (uu), and 3 parents bore green-shouldered fruit (UU). Data were collected during 6 harvests for both BER incidence (%) and severity (lesion size). Significant differences existed among the F1 genotypes UU, Uu, and uu for BER incidence (P=5%) and severity (P=l%). BER incidence tended to increase as the u allele increased from 0 to 2.
Abstract
The use of MagAmp as a nutrient source in 6 low Ca media reduced blossom-end rot (BER) incidence in ‘Patio Hybrid’ tomato. When Osmocote alone supplied the nutrients, BER incidence was significantly higher than when MagAmp was the sole nutrient source. A combination of MagAmp and Osmocote significantly reduced BER incidence below that observed when Osmocote was the sole nutrient source. Indirect evidence that Mg may have substituted for Ca in maintaining normal metabolism of the fruit is presented.
Abstract
Reciprocal cross differences and combining ability in Lvcopersicon esculentum, Mill, were investigated using a diallel crossing technique. Six inbred lines with diverse origins were utilized to investigate differences and combining ability for components of yield, fruit quality attributes, radial fruit cracking, and blossom-end rot (BER).
Significant reciprocal differences were observed for fruit number, early yield, percentage early yield, and BER incidence (%). Missouri line 76-1-60-8 was the female parent in the majority of crosses showing significance for high early yield. In 60% of the crosses in which it was involved, small-fruited PI 118785 produced significantly fewer fruits when it was used as the female. The data suggest that either maternal or cytoplasmic influences were manifest for these characters by these lines.
Fruit quality traits tended to show prevalence of general combining (additive) effects, whereas significant specific combining ability effects indicated dominance fo fruit weight.
Abstract
The variability, mode of inheritance, and gene action for soluble solids was studied in a cross of 2 divergent lines, Mo. Accession 223, a selection of PI 272689, and 1-417-1. About 3 gene pairs were indicated to control soluble solids. Additive gene action accounted for a heritability of about 35%. In the broad sense, heritability was about 59%, suggesting that non-additive genetic variance was about 25%. Evidence for dominance and for epistatic interactions of genes appeared to be lacking.
Abstract
In a diallel study involving 5 unrelated tomato lines, the mean values of non-parental single crosses for fruit weight, soluble solids, and titratable acidity were found to predict with confidence the performance of double crosses. No significant correlation was obtained between the observed and predicted fruit pH values. The small magnitude of difference among the observed values involving the same lines in a series of double crosses and the small magnitude of variation among the single crosses made it difficult to establish the best order of combining the lines in a double cross.
Abstract
The variability, mode of inheritance, and gene action for tomato fruit weight was studied in a cross of 2 divergent lines, Mo. Accession 223 (a selection of USD A P.I. 272689), and 1-417-1. The data indicated that more than 10 gene pairs, and possibly as many as 20, differentiated the parents for fruit weight in this cross. Partial dominance of small fruit weight genes was shown. No evidence of epistatic interaction was found. Gene action was largely geometrically cumulative. Heritability estimates in the broad sense was 29%. Little additive genetic variance was detected.
Abstract
Fertilization of tomato (Lycopersicon esculentum Mill.) in solution culture with NH4-N resulted in reduced shoot and root concentration of Ca, Mg, K, P, and NO3, increased leaf and root resistances to water flux, and decreased water use efficiency as compared to plants cultured with NO3-N. Solution adjustment to pH 6.5 decreased shoot/root fresh weight ratio with both N forms; decreased leaf diffusive resistance and water stress but increased root resistance to water flux and shoot NH4 concentration under NH4-N nutrition. Solution pH had little effect on tissue ion concentration.
Abstract
The practical significance of incorporating TMV resistance into F hybrid tomatoes can hardly be over-estimated. Internal browning, graywall and blotchy ripening disorders continue to plague the greenhouse tomato grower and constitute perhaps his greatest current disease problem. Lewis and Taylor (6) pointed out the confusion which exists with regard to the association of TMV with these disorders.
Abstract
Decreasing soil water potential (minima of −0.3, −2.0 and −6.0 bars) reduced fruit number, set, and mean and total fruit weight of tomato (Lycopersicon esculentum Mill). Under the 2 wettest soil water regimes, NH4-N compared to NO3-N fertilization reduced total and mean fruit weights but increased fruit number whereas no differences in these variables were found between N-forms under the driest regime. Incidence and severity of blossom-end rot (BER) were increased by NH4 nutrition and by decreasing soil water potential (SWP). Decreasing SWP either had no effect or increased leaf Ca, Mg, and K concentrations but decreased fruit concentration of these ions. At any soil water regime, NH4 fertilization decreased leaf Ca and Mg concentration but generally increased leaf K and fruit Ca, Mg, and K concentrations. While BER incidence and severity did not appear to be related to fruit Ca, Mg, and K concentration, the disorder was associated with increased stylar to calyx fruit-half concentration ratios of these ions. Basal (pre-dawn) leaf xylem pressure potential (ψ p) was unaffected by N nutrition but was greater (less negative) under the wettest regime. Compared to plants supplied with NO3-N whose minimal and mean light-saturation ψ p values decreased with decreasing SWP, plants given NH4-N reached a constant ψ p level regardless of soil water regime. Since leaf diffusive resistance (RL) values increased with decreasing SWP, but were unaffected by N form, the lower transpiration and transpiration rates under NH4-N might be explained by increased non-leaf resistances to water flux and/or by reduced soil-plant water potential gradients.