( Harborne, 1976 ). Flowers can accumulate mixtures of anthocyanin types, providing further variation in color. Other factors such as vacuolar pH and petal cell shape can also affect the flower color ( Mol et al., 1998 ). The genetics of flower color are best
Somatic cell genetics is a relatively new discipline which relies upon various plant tissue culture techniques. This discipline may be defined broadly as any genetic or physiological investigation involving cultured cells, and includes such areas as gene transfer, gene regulation, cell selection for genetic variants, control of development, and regulation of metabolism.
Attention here will be confined to those non-profit groups that serve to exchange information and materials related to genetics and breeding of specific horticultural crops. Being independent of the formal scientific societies and having arisen electively according to demand, they are highly heterogeneous in regard to functions, organization, support, and even titles. In most respects this heterogeneity is commendable since the needs of the various groups differ, and each group develops a distinctive character. It is beyond the scope of this article to present all the details of each cooperative, but they will be compared in respect to the most important aspects of their structure and functions. I hope to avoid an excessive slant toward the Tomato Genetics Cooperative, with which I have been associated since its inception. Excluded from major consideration in this article are groups devoted exclusively to line testing (ex. Southern Tomato Exchange Program, STEP), those covering an entire crop group (e.g. Vegetable Improvement Newsletter, VIN; Small Fruit Workers, SFW), or those which are restricted regionally.
., 1992 ). The zt1 and zt2 genes have been genetically mapped in faba bean chromosomes 2 and 3, respectively ( Gutierrez and Torres, 2019 ; Zanotto et al., 2020a ). Previous work on the genetics of red and yellow-spotted flowers has been limited to
This is an age of transition for horticultural plant breeding. The recent developments in physiological and biochemical genetics and their application to plant breeding signify only the beginning of this new era. To define the term New Genetics is extremely difficult especially when it is applied to horticultural plant breeding. For the purpose of this paper New Genetics will mean all of. those methods, machines, ideas and information that can assist in the future breeding of better horticultural plants.
Molecular Genetics and Breeding of Forest Trees. Sandeep Kumar and Matthias Fladung (eds.). 2004. Food Products Press, an imprint of the Haworth Press, Inc., 10 Alice Street, Binghamton, NY 13904-1580. 436 pages. $59.95 softbound. < www
The genetics of high-temperature fruit set was studied with a complete diallel cross using 5 cultivars with excellent high temperature tolerance and a California cultivar lacking stigma exsertion. The cultivars differed genetically for number of flowers per cluster, percent fruit set, number of seeds per fruit and stigma exsertion. At normal and high temperatures recessive genes are associated with greater flower number and heritability for this character was high. Percent fruit set is under the control of a largely additive system with a moderate heritability at high temperature. Nonallelic gene interaction was involved in seed set and dominance components exceeded additive at both temperatures. Heritability for seed set was low at high temperature. Stigma exsertion at high temperature is controlled by partially dominant genes with a high diallel additive component and heritability. The results suggest that a scheme of selection for specific combining ability would be useful to combine the strengths of the high temperature tolerant lines with needed characters from a successful cultivar.