Fred M. Bourland

Physiological Rationales in Plant Monitoring and Mapping

Cotton is an indeterminate crop that produces both vegetative and reproductive growth at the same time. Yield, earliness, and quality factors can be influenced by the balance between the two sinks. As a result, growth, development, and yield are responsive to changes in environment, and management adjustments must be designed to optimize the environment. Cotton management expertise has historically been an art acquired through years of experience. Skilled managers anticipate how the crop will respond to changing environments. Cotton monitoring and mapping provide a means to quantify growth and development and increase the precision of management decisions. It offers a tool to take cotton management from an art to a science.

Valuing Transgenic Cotton Technologies Using a Risk/Return Framework

Stochastic Efficiency with Respect to a Function (SERF) is used to rank transgenic cotton technology groups and place an upper and lower bound on their value. Yield and production data from replicated plot experiments are used to build cumulative distribution functions of returns for nontransgenic, Roundup Ready, Bollgard, and stacked gene cotton cultivars. Analysis of Arkansas data indicated that the stacked gene and Roundup Ready technologies would be preferred by a large number of risk neutral and risk averse producers as long as the costs of the technology and seed are below the lower bounds calculated in this manuscript.

Inheritance of resistance to seed deterioration in cotton

SummaryDeterioration of cotton, Gossypium hirsutum L., seed can adversely affect stands, seedling vigor, and subsequent performance of plants, but deterioration can be lessened by improved genetic resistance. This study was conducted to evaluate the relationship of physical and germination characteristics of cotton seed and to determine the inheritance of resistance to seed deterioration. Physical (weight, volume, density, and imbibition rate) and germination (germination of non-deteriorated seed and deteriorated seed) characteristics were determined for eight cotton genotypes. In addition, imbibition rate and the germination characteristics were determined for all possible F1, including reciprocals, combinations of the eight genotypes. Variation among the parents for germination of deteriorated seed and imbibition rate were significantly, highly correlated (r=−0.97) and intrinsically related. Resistance to seed deterioration tended to increase as seed weight and volume decreased. Significant genetic effects were found for imbibition rate and germination of both non-deteriorated and deteriorated seed. However, general combining ability (GCA) accounted for only 21% of the variation in crosses sums of squares for germination of non-deteriorated seed. In contrast, GCA accounted for 90% of the variation for germination of deteriorated seed and imbibition rate. A breeding approach involving selection of early generation seed for ability to survive hot water treatment, then evaluating later generations for imbibition rate is suggested as a means to improve resistance to seed deterioration in cotton.

A diallel analysis of seedling growth in cotton

Abstract The relationships among seedling measurements and the inheritance of seedling growth of cotton, Gossypium hirsutum L., in a controlled environment were studied using a diallel cross of eight parents. The parents included six strains from the Multi-Adversity Resistance (MAR) program and two commercial cultivars. Variation in root length on the fourth day after planting did not vary among the parents. The MAR strains generally had slower root elongation, measured by root length on day 9, than did the two cultivars. Variation in velocity of emergence indicated some parents established longer roots before emergence than did other parents. Variation in hypocotyl length on days 10 and 18 reflected differences in emergence speed. The rate of hypocotyl elongation, measured as the difference between day 10 and day 18 hypocotyl lengths, was similar for all parents. The parental and offspring data showed similar trends for velocity of emergence, day 9 root length and day 18 hypocotyl length. Offspring of parents which had extreme values for the traits expressed approximately mid-parent values. The offspring of parents which had similar values frequently were heterotic. However, the direction of heterosis shown by offspring of parents having high values was opposite to that shown by offspring of parents having low values. An explanation involving duplicate gene action and epistasis is proposed.

Diversifying Soybean Production Risk Using Maturity Group and Planting Date Choices

Due to the long growing season for soybean production, producers in the Mid-southern US can plant from late March to June. They also have a range of maturity group (MG) choices, affecting the length of the growing season, that are physiologically and economically viable. A producer’s decision of what to plant and when constitutes two potential decision variables that can be freely manipulated to not only maximize profit, but also reduce economic risk. Early maturing MG III and IV soybean cultivars planted early or mid-season typically are highest yielding and thereby the preferred choice of producers. However, planting part of a producer’s acreage at later dates and using later maturing MG VI soybeans may offer producers similar returns (as observed with early planting using early maturing cultivars) at a meaningfully reduced level of risk.

The influence of seed quality on response of cotton seedlings to the preplant herbicide trifluralin

Abstract Effects of the preplant herbicide trifluralin ( a , a , a -trifluoro-2,6-dinitro- N , N -dipropyl- p -toluidine) were studied on cotton ( Gossypium hirsutum L.) seedlings derived from seeds of four cultivars subjected to accelerated aging. Trifluralin effects were determined by measuring stand, lateral root production, damage to taproot, and seedling height. These parameters were measured under laboratory and field conditions. The tests were designed to evaluate the combined effects of trifluralin and seed quality on seedling emergence and development. The detrimental effects of seed aging and trifluralin were similar in the four tests. The adverse effects of seed aging were reduced stand, increased numbers of damaged taproots and decreased seedling height. Significant cultivar by aging interactions for stand were detected. Trifluralin reduced seedling height in the laboratory tests but to a lesser extent than the adverse effect of aging. Trifluralin had minor effects on stand and taproots but caused a drastic reduction in number of lateral roots. The trifluralin by aging interaction was significant for lateral roots in three of the four tests. Therefore, seed quality must be carefully considered when evaluating responses of seedlings to trifluralin. The absence of a consistent cultivar by trifluralin interaction for lateral roots indicated minor difference in tolerance to trifluralin among these cultivars.