Stella K. Kantartzi

Soybean Seed Amino Acid Content QTL Detected Using the Uni- versal Soy Linkage Panel 1.0 with 1,536 SNPs

1 Current address: Clemson Pee Dee REC, Advanced Plant Technology Center, 2200 Pocket Road, Florence, SC 29506, USA; 2 University of Tennessee, Department of Plant Sciences, 2431 Joe Johnson Dr., Knoxville, TN 37996, USA; 3 Monsanto, 140 W. Industrial Drive, Harrisburg, SD 57032, USA; 4 University of Arkansas, Department of Crop, Soil, and Environmental Sciences, Fayetteville, AR 72701, USA; 5 Southern Illinois University, Department of Plant, Soil Science and Agricultural Systems, 1205 Lincoln Drive, Carbondale, IL 62901, USA; 6 Soybean Genomics and Improvement Laboratory, Beltsville Agricultural Research Center – West, USDA, ARS, Beltsville, MD 20705, USA; 7 Current address: DuPont Pioneer, 8305 NW 62nd Ave., PO Box 7060, Johnston, IA 50131-7060, USA.

Quantitative Trait Loci (QTL) that Underlie SCN Resistance in Soybean (Glycine max (L.) Merr.) PI438489B by 'Hamilton' Re- combinant Inbred Line (RIL) Population

1 Plant Genomics & Biotechnology Lab, Department of Biological Sciences, Fayetteville State University, Fayetteville, NC, USA; 2 Department of Plant, Soil, and Agricultural Systems, Southern Illinois University, Carbondale, IL, USA; 3 Soybean Genomics and Improvement Lab, 10300 Baltimore Ave, Bldg. 006, Rm. 201, Beltsville, MD 20705; 4 Unite de Recherche En Genomique Vegetale, INRA, Ivry, France; 5 USDA-ARS Midsouth Area, Jackson, TN, USA; 6 Department of Agriculture, Alcorn State University, Alcorn State, MS, USA; 7 Plant Pathology Department and Agronomy Department, Iowa State University, Ames, IA 50011-1010.

Comparison of Early and Conventional Soybean Production Systems for Yield and other Agronomic Traits

The early soybean production system (ESPS) was reported to be beneficial for yield compared to the conventional soybean production system (CSPS) and is widely used in the Southern USA. The objective of this study was to compare yield, yield components, root traits, and shoot traits in ESPS (April planting) and CSPS (June planting) in NC Sandhills using a recombinant inbred line (RIL) population, ‘Hartwig’ by ‘Flyer’ (n=92). The population was grown in Spring Lake, NC in 2008 at a density of 16 seeds m-2. The traits measured were days to germination, days to flowering, plant height, seed weight, seed number, pod number, harvest index, root fresh weight, root dry weight, shoot fresh weight, shoot dry weight, maximum root length, and lateral root number. The survival rate ranged from 83.7 to 90.22% for ESPS; however, it was 21.74% for CSPS. Significant differences were observed for almost all traits measured in ESPS (April) compared to CSPS (June) apart from fresh root weight and lateral root number. An average increase in flowering time of 9 days was observed in CSPS compared to ESPS. On the other hand, several traits showed a significant mean decrease in CSPS compared to ESPS as plant height by 41.96%, seed weight by 74.7%, harvest index by 73.3%, pod number by 65.2%, and seed number by 64.9%. The means for root fresh weight, root dry weight, shoot fresh weight, shoot dry weight, maximum root length, and lateral root numbers are shown in Table 2 for both ESPS and CSPS. The results indicated an average decrease of 40.4% in root fresh weight, of __________________________________________________ * Corresponding author: mkassem@uncfsu.edu. 70.2% in root dry weight, of 68.1% in shoot fresh weight, of 80.1% in shoot dry weight, and of 83.3% in maximum root length in CSPS compared to ESPS. However, lateral root numbers increased by an average of 12.7% in CSPS compared to ESPS. Therefore, CSPS may not be appropriate for soybean at least in NC Sandhills.

Breeding barriers between Gossypium spp. and species of the Malvaceae family

Cotton breeders have long recognised the importance of alien germplasm from the Malvaceae family, especially the cultivated species, as sources of genes for cotton improvement. An understanding of the biological nature of the incompatibility systems that prevent hybridisation and/or seed development is necessary for the successful hybridisation and introgression between cotton and cultivated Malvaceae species (Hibiscus cannabinus and Abelmoschus esculentus). The objectives of the present study were to determine the reasons for reproductive isolation between Malvaceae species. The current study utilised two alien Malvaceae species and established that pollen–pistil incompatibilities are the primary reasons that hybrids with Gossypium hirsutum are not obtained. The alien pollen tubes showed major inhibition of growth in cotton pistils and seldom grew beyond the stigma. Only pollen tubes of A. esculentus grew into the ovary of cotton.

New Screening Strategies for Dinitrogen Fixation in Soybean

Improvement of biological nitrogen fixation is a critical step to increase crop yield in soybean. This review presents different strategies, both conventional and molecular, that have been used for developing new improved lines using traits that are directly and indirectly related to nitrogen fixation activity during the plant growth cycle.

Genetic Architecture of Soybean Yield and Agronomic Traits

Soybean is the world’s leading source of vegetable protein and demand for its seed continues to grow. Breeders have successfully increased soybean yield, but the genetic architecture of yield and key agronomic traits is poorly understood. We developed a 40-mating soybean nested association mapping (NAM) population of 5,600 inbred lines that were characterized by single nucleotide polymorphism (SNP) markers and six agronomic traits in field trials in 22 environments. Analysis of the yield, agronomic, and SNP data revealed 23 significant marker-trait associations for yield, 19 for maturity, 15 for plant height, 17 for plant lodging, and 29 for seed mass. A higher frequency of estimated positive yield alleles was evident from elite founder parents than from exotic founders, although unique desirable alleles from the exotic group were identified, demonstrating the value of expanding the genetic base of US soybean breeding.