Submitted to: Journal of American Society of Horticulture Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/5/1999
Publication Date: N/A
Citation: Interpretive Summary: The most prevalent environmental stress affecting plants is lack of water. Plant growth and fruit yield of cucumber are significantly affected by plant exposure to drought (lack of water) conditions. There are cucumber plants of different sizes (short and tall) and have different leaf sizes (large and small). These traits in cucumber are controlled by single genes (inheritance factors consisting of DNA). By crossing short, large leafed plants with tall small leafed plants and then continued matings of the progeny, nearly identical twins were developed which differed only in these genes (i.e., tall and small leaf, tall and large leaf, small and small leaf, small and large leaf) by extensive genetic manipulation (cross pollinating). A study was then designed to test the differences in reaction of these four different, but nearly identical plants to water stress (drought). It was determined that the tall and small leaf plants were not as affected in the plant growth stages (less wilting and higher fruit yield) as the other plants. However, fruit taken from tall and small leaf plants subjected to water stress had lower quality than the other plants. Therefore, a plant can be drought resistant in the growth stages (from flowering to beginning of fruit development), but still produce poor quality fruit. This research gives the cucumber grower information that will assist in making more refined irrigation schedules to increase cucumber production efficiency by reducing the effects of water stress on plants. The plant types developed provides the cucumber breeder with plants from which water stress tolerant varieties.
Technical Abstract: Four nearly-isogenic cucumber lines (Cucumis sativus L.) differing in leaf size [standard leaf (LL) vs. little leaf (ll)] and plant habit [indeterminate (DeDe) vs. determinate (dede)] were compared for their response to high soil moisture tensions in 1990 and 1996. Postharvest treatment affected the quality of fruit recovered from plants subjected to water stress. Exposure of fruits at 15C and 85% relative humidity (RH) for four days after hydrocooling, resulted in lower PFD than storage of fruit at 26C and 60% RH for two days without hydrocooling. Cucumber genotypes showed differential response to water stress indicating that plant habit and leaf size can be important genetic determinants of a cucumber plant's response to water stress. Although plant productivity was not affected by water stress, PFD, shape, seed size, and seed cavity size of fruit from lldede plants was more severely affected by water stress than its llDeDe counterpart. Plants homozygous ll, in either a determinate or indeterminate background, were less susceptible to wilting under water stress conditions than their normal leaf (LL) counterparts. However, plant dry weight and fruit number and weight were higher in LLDeDe plants when compared to their llDeDe counterpart. Fruit recovered from LLDeDe plants were of higher quality than those observed in fruit recovered from llDeDe plants. Thus, wilting response to water stress is not necessarily indicative of a cucumber plant's tolerance to water stress in the reproductive stage.