Search Results
You are looking at 1 - 3 of 3 items for :
- Author or Editor: Avtar K. Handa x
- HortScience x
Abstract
Water availability is one of the principal environmental limitations of crop productivity throughout the world. The water deficits, which are a consequence of either continuous or transitory periods of drought, cause significant yield reductions on presently cultivated land, and greatly restrict the cultivation of crops on over one-third of the earth’s land surface considered to be arid or semiarid (25). These restrictions on yield potential are rapidly becom ing of great concern in the face of the food demands of an ever increasing world population. The problem becomes complicated further by the fact that supplies of suitable irrigation water are dwindling rapidly, and that the costs of irrigation are becoming prohibitive. As a result, studies on the effects of water stress on plant survival and yield are attracting added interest in plant science research.
Abstract
Salinity is a significant limiting factor to agricultural productivity, impacting about 9 × 108 ha of the land surface on the earth, an area about 3 times greater than all of the land that is presently irrigated (17, 18). Reduced productivity occurs as a result of decreased yields on land that is presently cultivated [about one-third of all irrigated land is considered to be affected by salt (18, 45)], as well as due to the restriction of significant agricultural expansion into areas that presently are not cultivated. In the United States, salinity is a major limiting factor to agricultural productivity, and as the quality of irrigation water continues to decline this problem will become more acute (1, 56). About 1.8 million ha of land are salt-affected in California (56), the major agricultural state in the nation. Annual losses to crop production in the salt-affected areas, including the Imperial, Coachella, and San Joaquin valleys, are substantial and are increasing at a significant rate each year (56).
We have introduced an antisense pectin methylesterase (PME) gene into Rutgers tomato to elucidate its role in fruit development and ripening. In greenhouse trials tomato fruits from transformant 37-81^ homozygous for the antisense PME gene ripened normally and contained higher levels of soluble solids than wild-type Rutgers fruits (Tieman et al. (1992) Plant Cell 4:667-679). Field trials of transgenic 37-81^ homozygous and azygous for the antisense PME gene and wild-type Rutgers were conducted during the summer of 1992. Field grown fruits from homozygous 37-81^ plants have significantly higher levels of soluble solids and total solids and a higher fruit pH than Rutgers or 37-81^ azygous fruits. Average fruit weight did not differ significantly in the three genotypes, but 37-81^ (homozygous) plants had a higher total fruit yield than Rutgers or 37-81^ azygous plants. Plant fresh and dry weights did not differ significantly among the three plant types.