Molecular breeding

About: Molecular breeding is a research topic. Over the lifetime, 2120 publications have been published within this topic receiving 56908 citations.

Genes Controlling Plant Root Growth and Development for Stress Tolerance and Method of Their Use

Abstract: Microarrays are employed to analyze soybean transcriptome under water stress conditions in different regions of the root at vegetative stage. Drought responsive genes and transcription factors are identified which may be used for enhancing drought tolerance in soybean or other plants through genetic/metabolic engineering. This disclosure pertains to nucleic acid molecules isolated from soybean and maize that encode polypeptides that may be important for drought tolerance. The disclosure also relates to methods of using these genes from soybean in transgenic plants to confer the desired agronomic traits, and to use such genes or regulatory elements thereof to assist germplasm enhancement by molecular breeding or to identify other factors or chemicals that may enhance a plant's capability to grow under drought conditions.

Estimating genetic parameters and the efficacy of molecular breeding for resistance to the stalk borer Eldana saccharina.

Abstract: BREEDING for resistance to the stalk borer Eldana saccharina is one of the goals of the SASRI variety improvement program being addressed through an integrated approach involving conventional and molecular breeding. The objectives of this study were: to evaluate a mass screening method to estimate eldana resistance at a family level; to estimate narrow-sense heritability of eldana resistance, as well as family repeatability of resistance; and to attempt an initial verification of the efficacy of molecular breeding for resistance. Seedlings from 36 bi-parental crosses were planted at high density and inoculated with eldana larvae at 6 months of age. Phenotypic data for eldana resistance of the parents of the crosses were available, and the parents had been characterised for eight previously identified marker loci that ascribe 37% of the phenotypic variation in resistance. After one month, plots were harvested, eldana damage was measured and subjected to appropriate analysis. Mean stalk length damaged was highly significant between families. Variance components estimated by REML gave a family repeatability of 0.90, indicating that the mass-screening method was highly effective in estimating eldana resistance on a family level. Heritability calculated from phenotypic mid-parentoffspring regression was estimated at 0.57 explaining 12.6% of the variation in resistance at the family level. Heritability estimated from molecular marker prediction was 0.82, explaining 19.2% of the variation in progeny resistance. Molecular markers have apparently been effective in breeding for eldana resistance. Using sets of markers exhibiting stronger association with resistance may further increase the efficiency of molecular breeding. Introduction The African sugarcane stalk borer Eldana saccharina Walker (Lepidoptera: Pyralidae) is a major insect pest of sugarcane in South Africa, causing extensive damage especially when cane is under stress. Larvae enter the stalk about one week after hatching where they are protected from exposure, with the result that insecticidal control is variable and not widely practised. Host-plant resistance and cultural practices such as early harvesting have been, and will continue to be, the main methods of limiting damage caused by the insect. Development of eldana resistant cultivars is one of the goals of the South African Sugarcane Research Institute’s (SASRI) breeding program, and eldana damage is routinely measured in variety selection trials at SASRI's Gingindhlovu research station. In addition to eldana assessment in yield trials, all promising individuals are screened in eldana inoculation trials conducted under controlled conditions in a shade-house, and resistance ratings are assigned, based on statistical principles as described by Keeping (2006). The scale used is a modified version of the ISSCT-published scale (Hutchinson, 1968), where low values (1, 2, and 3) indicate resistance, and high values (7, 8, 9) indicate susceptibility.

Molecular Tools for Plant Breeding

Abstract: Molecular techniques will have an enormous impact on plant breeding. Marker-assisted selection and marker-based genetic distance analysis are presently used for many breeding programs. They help to accelerate backcrossing procedures and to predict the performance of progeny. Furthermore, genetic engineering tools offer interesting alternatives for crop production. In particular, they can facilitate the development of plants with better pest and disease resistance and improved quality characteristics. Such transgenic plants have undergone extensive safety studies and were commercially grown on 40 million hectares worldwide in 1999. Nevertheless, breeding in the laboratory alone will never be a realistic alternative, and so future plant breeding will continue to rely on traditional procedures of selection and field-testing. Locally adapted varieties will be fundamental whether transgenic technologies are employed or not.