For three Asiatic hybrid lily cultivars ('Bright Beauty', 'Fashion', 'Orlito') the potential postharvest performance of floral buds in terms of growth, anthesis and longevity was studied in relation to tepal carbohydrate status. To determine the importance of carbohydrate redistribution within lily inflorescences, the postharvest performance of several attached and detached buds was compared at the time of anthesis of the most mature floral bud of the inflorescence. Detachment of buds increased failure of opening in small buds, whereas in the largest buds tepal size at anthesis and longevity were improved. In lily inflorescences, postharvest translocation of substrate from the basal to the upper buds takes place. Five bud classes have been characterised, comparing the postharvest performance of attached and detached buds. Classes were based on differences in tepal growth rate, absolute growth and the potential to reach anthesis. A bud length of about 60 mm at harvest, appeared to be critical for reaching anthesis of detached buds. Comparable bud development and flower longevity of inflorescence-attached and inflorescence-detached floral buds was determined in buds of 70-75 mm. At this bud length the total carbohydrate content (fructose, glucose, glycerol glucoside, starch, sucrose) covered about three-fourths of the total tepal carbohydrate content found in the largest bud stage just prior to anthesis. Per cultivar, postharvest flower longevity after anthesis of detached buds was well correlated with total carbohydrate content of the tepals at harvest. Longevity of inflorescence-attached flowers remained constant within the inflorescence, likely due to postharvest redistribution of tepal carbohydrate. These findings indicate an important role for tepal carbohydrate content in postharvest bud development and flower longevity of Asiatic hybrid lilies. Carbohydrate redistribution is suggested to play a major role in the postharvest performance of Asiatic lily inflorescences.

Genotypic variation in postharvest flower longevity was determined for 63 Asiatic lily hybrids (Lilium L.). The reliability of standardized test conditions for longevity screening was also examined. Improvement of lily flower longevity by breeding appears feasible. Considerable genotypic variation in individual flower longevity was obtained and estimates of the degree of genotypic determination were high. The rank order of the genotypes with respect to individual flower longevity was similar between years using standardized test conditions. Screening results for flowers forced in a growth chamber were similar to those obtained in a greenhouse. No plant traits suitable for indirect selection on flower longevity were detected.

Growth analyses were carried out on young plants of 15 genotypes, grown initially at 19/14 degrees C day/night temperatures for an 8 h day at low light intensity and subsequently at the night temperatures of 6, 10 and 14 degrees C. Significant genotypic differences occurred for relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR), specific leaf area (SLA) and leaf weight ratio (LWR). RGR, LAR and SLA increased and LWR decreased at higher night temperatures. A strong negative correlation was observed between NAR and LAR and NAR and SLA whilst a positive correlation was noted between LAR and SLA. Plant weight was strongly influenced by seed size. (Abstract retrieved from CAB Abstracts by CABI’s permission)

A study w-as made on the inheritance of seed weight of tomato, and on the effect of seed ti'eight on growth of tomato plants. Use w-as made of 15 parental genotypes and 105 F,'s produced by diallel crossing (Fi-seeds). From combining ability analysis of variance carried out for weight of F-seeds it appeared that the weight of seeds harvested from tomato plants was mainly determined by the maternal genotype and largely independent of the genot)-pe of the male parent. A combining ability anah-sis of variance for weight of seeds produced by selfing F|'s (Fi-seeds) showed, how-ever, that female and male parents contributed equalh-to the inheritance of seed weight and that the inheritance of seed weight is determined mainly by chromosomal additively acting factors, but that also non-additive gene action occurred.Genotypes with large seeds produced heavier seedlings than genotypes with small seeds. In later grow-th stages, the correlation between seed w-eight and plant -n-eight became smaller, presumably, due to a lower relative growth rate of the seedlings from large seeds. For this reason, it is doubttui whether breeding of large seeded tomato cultivars opens up prospects of improving growth and yield of tomato plants.

Nongenetic variation in cut flower longevity due to plant characteristics was investigated in whole inflorescences and individual flowers of Asiatic hybrid lilies (Lilium L.). To distinguish this variation from genetic variation, plant characteristics of five cultivars were varied by using bulbs of three significantly different weight classes per cultivar. Inflorescence longevity depended on total number of floral buds, number of buds opening and variation in bud length. Variation in individual flower longevity per cultivar appeared to be small, despite a larger number of buds per stem with increasing bulb weight. Plant characteristics caused only small nongenetic variation in individual flower longevity when compared to inflorescence longevity. Therefore, individual flower longevity appears to be the best criterion to discriminate among longevity levels for a lily breeding program.