Search Results
Abstract
The effect of salinity (0 to 0.12 M NaCl) and temperature (20-30°C) on germination of ‘Phoenix’ lettuce seed was studied. Increasing levels of both factors inhibited germination and reduced fresh weight of young seedlings. The salinity by tempertaure interaction was found to be statistically significant in the inhibition of germination. Although the mechanism of this interaction is not known, it was found that osmotic inhibition was reduced at lower temperatures. Kinetin largely overcomes both temperature and osmotic inhibition of germination, but its effect on early seedling development varies with temperature. At 15° no significant effect was observed, but at higher temperatures (23° and 25°) it increased fresh weight at higher salinity levels but had no effect at lower salinity levels.
A pilot sustainable rural initiative project was introduced to build capacity among trade associations consisting of women engaged in fruit agribusiness. The purpose was to improve production and encourage local processing of horticultural commodities of economic importance like citrus, pineapple and mango fruits. Training the trainer approach was used to extend simple techniques of food preservation including partial processing and juice bottling to potential entrepreneurs. Skills were transferred primarily to selected extension specialists who coordinate grassroots training. The training and visit technique was utilized to measure adoption rate among the rural people. Impact of the scheme on postharvest food loss reduction is discussed in this presentation; there is ample opportunity to optimize resource utilization and increase income generation through applied horticultural technology.
Abstract
Lettuce plants (Lactuca sativa L.) showed definite flowering peaks over a 70-day period. Over 90% of the seed yield was from flowers which opened during the first 35 days, and seed produced from flowers opening during the first 2 flowering peaks were heavier than those produced later in the season. Seed size was not correlated with number of seeds per flower head. Seed yield and quality were not affected by early harvest or by withholding water and nutrients during the last half of the flowering period. Flowering rate, seed yield, and seed quality were not related to air temperature in the range 67 to 94°F.
Abstract
Physical characteristics measured individually for each lettuce (Lactuca sativa L.) seed and its embryo were significantly correlated with seedling and plant growth (vigor) up to a certain stage, possibly heading, after which the correlations diminished. Embryo physical measurements, although slightly better correlated with subsequent vigor than seed (achene) physical measurements, were highly correlated with those of the whole seed.
Of the 5 physical measurements studied, all but length were found to be associated with early vigor. Thorough statistical analyses place seed and embryo physical characteristics in a consistent and significant order in determining vigor: weight > thickness > density (as measured by an air column) > width > length.
Abstract
Lettuce, Lactuca sativa L., plants were grown in soil irrigated at various intervals with nutrient solution and in hydroponics culture. Increased nutrient level added to the soil increased seed yield but did not give a corresponding increase in seedling performance.
Hydroponically propagated seed, although heavier than soil propagated seed, were relatively poor in vigor and germinability. A positive linear correlation was found between N levels (5-15 meq) and seed yield, weight per seed, and seedling vigor. Amounts of amino acids and lipids were not positively correlated with nutrient supply, N level, or seedling vigor. Lettuce seed weight was a useful parameter in predicting seedling vigor only within a seed lot obtained from plants grown under the same environmental and nutritional conditions.
Abstract
Several lots of lettuce seed were separated into fractions varying in seed width and weight per seed. Seed vigor, as measured by the slant test, was found to vary in relation to seed weight. In field trials low vigor seeds emerged slower with less total emergence and produced smaller seedlings at thinning time than high vigor seeds. Head size at harvest and percent marketable heads were greater from high vigor seeds. It is suggested that seed vigor can be used to evaluate potential field performance of lettuce.
Abstract
In the paper by O. E. Smith, N. C. Welch, and T. M. Little in J. Amer. Soc. Hort Sci. 98(6):529-533, November 1973, the following changes should be made on page 529, column 2, lines 28 and 35:
Line 28: change “transferred to a 1/15 M” to read “transferred to a 20-fold dilution of a 1/15 M”
Line 35: change “of the pH 7.0 phosphate” to read “of the pH 7.0 dilute phosphate”
If the buffer is used at 1/15 molar, the roots of the young plants will be injured due to the high osmotic strength of the buffer.
Abstract
Seed weight in lettuce was more important than seed width or thickness in predicting vigor. An air column separator was an effective way to separate seeds varying in weight. A biological assay called the slant test was developed to test vigor. The average root length after 3 days was used as a measure of vigor.