Ida Wenefrida

Mutational breeding and genetic engineering in the development of high grain protein content.

Cereals are the most important crops in the world for both human consumption and animal feed. Improving their nutritional values, such as high protein content, will have significant implications, from establishing healthy lifestyles to helping remediate malnutrition problems worldwide. Besides providing a source of carbohydrate, grain is also a natural source of dietary fiber, vitamins, minerals, specific oils, and other disease-fighting phytocompounds. Even though cereal grains contain relatively little protein compared to legume seeds, they provide protein for the nutrition of humans and livestock that is about 3 times that of legumes. Most cereal seeds lack a few essential amino acids; therefore, they have imbalanced amino acid profiles. Lysine (Lys), threonine (Thr), methionine (Met), and tryptophan (Trp) are among the most critical and are a limiting factor in many grain crops for human nutrition. Tremendous research has been put into the efforts to improve these essential amino acids. Development of high protein content can be outlined in four different approaches through manipulating seed protein bodies, modulating certain biosynthetic pathways to overproduce essential and limiting amino acids, increasing nitrogen relocation to the grain through the introduction of transgenes, and exploiting new genetic variance. Various technologies have been employed to improve protein content including conventional and mutational breeding, genetic engineering, marker-assisted selection, and genomic analysis. Each approach involves a combination of these technologies. Advancements in nutrigenomics and nutrigenetics continue to improve public knowledge at a rapid pace on the importance of specific aspects of food nutrition for optimum fitness and health. An understanding of the molecular basis for human health and genetic predisposition to certain diseases through human genomes enables individuals to personalize their nutritional requirements. It is critically important, therefore, to improve grain protein quality. Highly nutritious grain can be tailored to functional foods to meet the needs for both specific individuals and human populations as a whole.

Inheritance of herbicide resistance in two germplasm lines of Clearfield* rice (Oryza sativa L.)

Inheritance of imidazolinone resistance in two germplasms of Clearfield rice lines, 93AS3510 and PWC-16, was studied using parents, F1 hybrids, F2 populations , and F2:3 families. Germination tests were conducted in Petri dishes under controlled environments to reveal any discrete phenotypic responses to herbicide treatments. PWC-16 has a herbicide resistance level 4.9 times higher than that of 93AS3510. A concentration of 1 mg L-1 a.i. (active ingredient) of imazethapyr herbicide produced three distinctive response types in 93AS3510 crosses, while a concentration of 10 mg L-1 was required to differentiate the three response types in PWC-16 crosses. The segregation of the herbicide-resistant gene from both Clearfield rice lines fit into the Mendelian 1:2:1 (susceptible:intermediate:resistant) ratio. There was no maternal effect associated with the inheritance of the trait. The imidazolinone resistance, therefore, is governed by a single incomplete dominant nuclear gene. The F1 hybrid from a cross between ...

Progression of DNA Marker and the Next Generation of Crop Development

Advancement in genomic technology has been the main thrust for the progression of DNA markers that is now approaching a critical point in providing a platform for the next generation of varietal development. Improving total yield production to meet the increasing need to feed the world population remains the major goal. However, achieving more sophistication in providing high quality crop products to meet the emerging demand for better nutritional values and food functionalities will increasingly become important goals. Progression in high throughput marker analyses, significant reduction in the cost per data point, sophistication in computational tools, and creation of customized sets of markers for specific breeding applications are continuing and expected to have direct implications for highly efficient crop development in the near future. An advanced DNA marker system can be used to accomplish breeding goals, as well as achieve various scientific goals. The goals encompass a wide array of targets from understanding the function of specific genes so detailed that the quality of gene output or products can be controlled to attaining a global view of genomic utility to improve crop development efficiency. The combination of molecular understanding at the individual gene levels and genetic manipulation at the genome levels may lead to a significant yield leap to meet global food challenges.

Use of an Airplane and Simulated Aerial Planting to Evaluate Seed Coating, Seed Pelletization, and Seeding Rate on Smooth Cordgrass Vegetation

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Herbicide and Weed Control in a Freshwater Seed Production Field of Smooth Cordgrass (Spartina alterniflora)

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