A study on the genetics and physiology of Antirrhinum majus L. cut flower postharvest longevity
Schroeder, Kenneth Roland
Ph.D., The University of Wisconsin - Madison, 2000, 152 pages
2001
บทคัดย่อ
Genetic analysis of Antirrhinum majus L. cut flower postharvest longevity (PHL) suggest PHL is quantitative and influenced by significant additive gene effects, and important dominance and epistatic interactions. Heritability was estimated at 78 and 30% broad and narrow sense, respectively. Two to 4 genes minimum control PHL. Several genes of large effect explain the majority of short PHL while long PHL likely involves many genes. Backcrossing to a long-lived parent with selection for flower color is a useful method of acquiring long-lived colored lines. Gain from selection for long PHL is attainable; however, due to environmental influence, slow progress is expected and replicated selection required.
Preharvest conditions, cut flower harvest weight and floral development influenced PHL. Best PHL was achieved when production temperature 2 to 6 weeks prior to harvest was 15°C compared to 30°C. Genotypes with lighter harvest fresh and dry weights had longer PHL. A 58% lower stem fresh weight was associated with 65% PHL increase. Additionally, flower opening rate is not directly related to PHL.
Fifty-three percent fewer stomata per cut flower is associated with 9 days longer PHL. Long PHL is associated also with initial rapid reduction in transpiration and maintenance of low steady transpiration. Short-lived genotypes had 22 to 33% reductions in fourth quarter transpiration, while long-lived had 2 to 8%. These large transpiration reductions and higher average fourth quarter fresh weight loss of the short-lived compared with long-lived genotypes indicate vascular occlusions may be associated with short PHL.
Soluble sugars (SS) studies suggest source-sink relations may be more important to PHL than total endogenous SS concentrations. In this study, long-lived cut flower petals had a higher percentage of total cut flower SS than short-lived petals. Also, although long-lived (WL) and short-lived (WS) inbred SS concentration dropped when grown at 30°C compared to 15°C, PHL for WL decreased 2.8 d and increased 1.3 d for WS.
Further investigation of stomatal numbers and functioning relative to PHL may provide breeders a rapid and nondestructive indirect selection for PHL. Additionally, the proposed vascular occlusion development and possible genetic control warrant further study.