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Abstract
Yield and quality are the primary goals of most plant breeding programs. Both of these general characteristics are multifaceted and extremely complicated. This complexity and a frequent negative relationship between them makes it difficult to deal successfully with them simultaneously in a breeding program.
Abstract
Threshing of large numbers of seed samples encountered in bean breeding programs has been a difficult problem to solve satisfactorily. In many cases, threshing has been done by hand with the aid of a small blower. Actual seed recovery is relatively efficient but it is painfully slow and tedious. With this method one person can normally thresh 10 to 15 small samples per hour.
Abstract
Changes in acid content in fruits of tomato (Lycopersicon esculentum Mill.) left on the vine compared with those of fruits removed from the vine at one stage each of development and ripening. Developing fruits detached 28 days after anthesis had an increase in total acidity attributable to increased malic and citric acid concentrations. Detached developing fruits accumulated organic acids more rapidly than attached fruits. Mature fruits detached at the breaker stage decreased more in total acidity than attached fruits which was reflected in a decrease in malic and citric acids, with a greater decrease in malic acid. The data indicate that organic acid accumulation in detached fruits is determined by metabolism at the time of detachment.
Abstract
Ilex X meserveae S. Y. Hu cvs. Blue Angel, Blue Maid, Blue Princess (pistillate) and Blue Prince (staminate) were planted around specially designed cross-shaped structures to determine tolerance to summer and winter stresses as affected by sun, shade, and wind patterns. Most plant damage occurred in the summer on the S and SW exposures where plant canopy and soil temperatures reached 43° and 48°C, respectively. All cultivars survived −23° in winter, but ‘Blue Angel’ was damaged. ‘Blue Princess’ was the hardiest and most fruitful cultivar. Shoot growth was greatest on ‘Blue Prince’ and ‘Blue Maid’. Plants performed best on the N, NE, and NW exposures, where summer temperatures were relatively cool and foliage temperature fluctuation were reduced in winter.
Abstract
Three of 6 antitranspirants significantly reduced winter injury 1 of 5 years when applied 1 and 2 times to Ilex × attenuata Ashe ‘Foster's No. 2’. No reduction of winter injury was observed during 1979 and 1980 even though leaf water potentials recorded during winter stress periods indicated that Exhalt 4-10, Vapor Gard, Wilt Pruf, Folicote, and Foligard significantly reduced transpirational loss of water in midwinter. Two applications of Folicote and Exhalt 4-10 increased water potential more than the single fall application, but did not reduce winter injury significantly. Clear Spray did not increase leaf water potential and appeared to crack and peel within 3 weeks aftef application. Scanning electron micrographs indicated better coverage of leaf surfaces by dipping them by spraying and verified the rapid cracking of Clear Spray.
Abstract
15N-labeled potassium nitrate was applied in a foliar spray to French prune/Marianna 2624 trees (Prunus domestica L.), and the nitrogen absorbed by the leaves was quantified. Nitrogen derived from a single foliar spray averaged 3% of total leaf nitrogen. L77, a non-ionic organosilicone surfactant which lowers surface tensions of aqueous solutions sufficiently for stomatal penetration, significantly enhanced the rate of NO3 absorption and increased incorporation of foliar-derived nitrogen into alcohol insoluble macromolecules. This enhancement was not apparent when labeled NO3 was applied with Regulaid, a carbohydrate-based non-ionic surfactant. About 25% of the foliar-derived N was apparently transported from leaves within 3 days when the stomatal penetrant was employed. No transport was evident in the absence of the penetrant.
Low-vigor seeds of black-eyed Susan (Rudbeckia fulgida Ait.) primed in aerated -1.3 MPa KNO3 for 7 days at 30C in darkness had double the total germination percentage at 30C and one-half the mean time of germination as nonprimed seeds. Priming the seeds in polyethylene glycol rather than KNO3 generally resulted in lower total germination percentage and longer mean time of germination. Osmotic priming increased total germination percentage and germination rate of seeds germinated at 21.9 to 32.2C, but the priming benefit on total germination percentage was greater at ≤27.6C. Total germination percentage of primed and nonprimed seeds was highest at 28.8 to 32.2C.
Germination trials of three seedlots were conducted over a temperature gradient for 14 days to determine the optimal germination temperature for the Black-eyed Susan (Rudbeckia fulgida Ait.). The optimal germination temperature for R. fulgida seeds was 30 ± 1C. All three seedlots began germination (radicle emergence) on the second day at 30.2C. By day four, all seedlots sur-passed 50% germination, with three seedlots germinating 53%, 52%, and 73%. Mean germination percentages were higher between 28.3 and 32.6C than at temperatures above or below this range. Significantly higher germination percentages and enhanced germination rates attained at the elevated temperatures may save time, cut production costs, and decrease exposure to detrimental pre-emergent pathogenic fungi.
Abstract
The inheritance of malate in tomatoes was investigated by gas-liquid chromatography with trimethylsilyl derivatives. Studies of progeny from the crosses ‘Campbell 146’ x ‘Campbell 1327’ and ‘Delsher’ x PI 255842-SI indicated that concentration of malate is determined by a single factor with dominance for low concentration.
The effect of foliar salt uptake on potted grapevine growth and ionic composition was investigated in a split plot trial. The main plot was a 2 × 2 factorial consisting of separately irrigating the roots and foliage with nonsaline or saline (25 mm NaCl) solutions. The subplot was a 4 × 2 factorial consisting of four grape (Vitis vinifera) cultivars on their own roots or `Ramsey' (Vitis champini) rootstock. Saline foliar irrigation over 27 weeks reduced total vine growth by 14% while saline root irrigation had no effect. Leaf Na and Cl concentrations were elevated by saline foliar and saline root irrigation. The increases in concentrations with saline foliar irrigation were four times those with saline root irrigation. Leaf K concentration was reduced by saline foliar irrigation and increased by saline root irrigation. With saline irrigation of roots and foliage the Cl and Na levels were highest in the leaves of `Shiraz', but with saline irrigation of only the roots `Sultana' had the higher levels of leaf Cl and `Shiraz' the highest leaf Na. Saline foliar irrigation had no effect on the concentrations of Na, Cl, and K in the roots. In `Sultana', saline foliar irrigation did not affect the leaf concentrations of N, NO3-N, P, Mg, Zn, and Cu. It increased the leaf concentration of Fe, and decreased that of Mn. Rootstock modified the effect of salinity on Fe concentrations. The B concentration was decreased by saline irrigation of either the foliage or the roots, but not by saline irrigation of both. In roots, saline foliar irrigation increased B in own-rooted vines, but not in those on `Ramsey' rootstock.