Nut Cultivars Research Articles

Genetic Transformation of Fruit and Nut Species

ABSTRACTProgress in application of genetic plant manipulations for improvement of the existing cultivars of fruit and nut species are discussed. The development of regeneration procedure and successful transformation system is cultivar dependent. Agrobacterium mediated gene transfer approach is the fruitful one. Transgenic plants expressing selectable and reporter genes were obtained for a number of fruit and nut genera. Useful genes encoding for proteins that are involved in diseases and pests resistance herbicide tolerance, fruit quality and growth architecture have been introduced in commercial fruit and nut cultivars. The propagation of genetically manipulated plants and their place in the fruit and the nut production, the environmental impact are also considered appropriately.

Response of groundnut to drought stress in different growth phases

The response of ground nut ( Arachis hypogaea L.) cultivar Robut 33-1 to drought stress imposed at different growth phases was studied during the 1982–83 post-rainy season on a medium deep Alfisol at the ICRISAT Center, Patancheru, India. Irrigation amount was varied to three levels for the growth phases: (1) emergence to flowering, (2) emergence to pegging, (3) start of flowering to start of seed growth, and (4) emergence to maturity. Soil water extraction in treatments 1 and 2 was mostly from the surface 60 cm of soil, whereas in treatment 3 extraction from the 60–120 cm soil layer was significantly higher. Total water use varied with the growth phase and also with the intensity of drought stress within a growth phase. Stress imposed in treatment 2 resulted in increases in pod number and dry matter. Significantly higher pod and kernel yields were obtained in treatment 2. Quality of kernels was also superior in treatment 2, as shown by the improved seed weight, oil and protein contents, and the percentage of seed to pod weight. In treatment 3, low yields and a lower percentage of sound mature kernels were observed. Drought stress imposed from flowering to start of seed growth was shown to be important for both yield and quality.

Genetic Remodeling of Fruit and Nut Trees to Facilitate Cultivar Improvement1

Abstract Numerous studies show there is great genetic variability in tree fruit and nut species (24). Where quantitative genetic analyses have been made they generally reveal that most of this genetic variability is additive (18, 19, 20, 21, 22). Consequently, the simplest, least expensive breeding method (mass selection) should be as effective as any for improving tree fruit and nut cultivars. Furthermore, most tree fruit and nut species are perennial and can be readily cloned (most commonly by bud grafting). These properties provide geneticists powerful engineering tools that are unavailable in most agronomic and vegetable species. Taken together, these facts suggest that the genetic techniques so successful in improving agronomic and vegetable cultivars should be even more effective when applied to tree fruit and nut crops. However, this is not the case because large plant size and long periods of juvenility severely impede the process of cultivar improvement in tree fruit and nut species.