Herry S. Utomo

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.

Current Patents and Future Development Underlying Marker-Assisted Breeding in Major Grain Crops

Genomics and molecular markers provide new tools to assemble and mobilize important traits from different genetic backgrounds, including breeding lines and cultivars from different parts of the world and their related wild ancestors, to improve the quality and yield of the existing commercial cultivars to meet the increasing challenges of global food demand. The basic techniques of marker-assisted breeding, such as isolating DNA, amplifying DNA of interest using publicly available primers, and visualizing DNA fragments using standard polyacrylamid gel, have been described in the literature and, therefore, are available to scientists and breeders without any restrictions. A more sophisticated high-throughput system that includes proprietary chemicals and reagents, parts and equipments, software, and methods or processes, has been a subject of intensive patents and trade secrets. The high-throughput systems offer a more efficient way to discover associated QTLs for traits of economic importance. Therefore, an increasing number of patents of highly valued genes and QTLs is expected. This paper will discuss and review current patents associated with genes and QTLs utilized in marker-assisted breeding in major grain crops. The availability of molecular markers for important agronomic traits combined with more efficient marker detection systems will help reach the full benefit of MAS in the breeding effort to reassemble potential genes and recapture critical genes among the breeding lines that were lost during domestication to help boost crop production worldwide.

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 ...

Suspension and protoplast culture of U.S. rice cultivars

Efficient protoplast culture and plant regeneration of five U.S. rice cultivars (Oryza sativa L.) - Mercury, Lacassine, Maybelle, Cypress, and Lemont - were obtained from suspension cells maintained in modified General Medium. Embryogenic suspension cells were developed from calli grown on the original callus induction medium for 10–20 weeks without subculture. Weekly subculture of the suspensions for five to eight weeks yielded cells suitable for protoplast isolation. After 2 weeks, rate of colony formation from protoplasts varied among the cultivars and ranged from 2.5 to 6.8%. Improvement of plating efficiencies to as high as 13.7% was obtained by conducting a second cycle of protoplast culture. A total of 525 plants were regenerated from the cultivars studied.

Growth and regenerability of long-term suspension cultures of the U.S. rice cultivar Mercury

Suspension cultures of the U.S. rice cultivar Mercury have been maintained in modified General Medium for more than 3 years. These suspensions have continued to have high and relatively stable regeneration rates. Two different explants, immature panicles and seeds, were compared during the development of these embryogenic suspensions. Initial formation of secondary embryogenic callus from immature panicles on induction medium was greater than that from seeds. Suspensions of these two cell lines, however, did not differ morphologically and maintained similar regeneration rates. After 5 months in culture the rates of regeneration began to decline. The suspensions were plated onto regeneration medium without growth regulators for 2 weeks and then embryogenic cells were manually selected and used to develop secondary suspensions. Through this simple rejuvenation procedure, the suspensions retained high and stable regeneration rates. Variability in suspension growth, however, was observed during the culture period. Slower growth occurred at weeks 13, 15, 27, and 29 and was associated with a decrease in regeneration rates. Reproductive fertility of regenerated plants remained high for 3.5 years but then declined.

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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