@article{zhang_gibon_wallace_lepak_li_dedow_chen_so_kremling_bradbury_et al._2015, title={Genome-Wide Association of Carbon and Nitrogen Metabolism in the Maize Nested Association Mapping Population}, volume={168}, ISSN={["1532-2548"]}, DOI={10.1104/pp.15.00025}, abstractNote={Genetic variants of maize identify genes and regions that control core carbon and nitrogen metabolism. Carbon (C) and nitrogen (N) metabolism are critical to plant growth and development and are at the basis of crop yield and adaptation. We performed high-throughput metabolite analyses on over 12,000 samples from the nested association mapping population to identify genetic variation in C and N metabolism in maize (Zea mays ssp. mays). All samples were grown in the same field and used to identify natural variation controlling the levels of 12 key C and N metabolites, namely chlorophyll a, chlorophyll b, fructose, fumarate, glucose, glutamate, malate, nitrate, starch, sucrose, total amino acids, and total protein, along with the first two principal components derived from them. Our genome-wide association results frequently identified hits with single-gene resolution. In addition to expected genes such as invertases, natural variation was identified in key C4 metabolism genes, including carbonic anhydrases and a malate transporter. Unlike several prior maize studies, extensive pleiotropy was found for C and N metabolites. This integration of field-derived metabolite data with powerful mapping and genomics resources allows for the dissection of key metabolic pathways, providing avenues for future genetic improvement.}, number={2}, journal={PLANT PHYSIOLOGY}, author={Zhang, Nengyi and Gibon, Yves and Wallace, Jason G. and Lepak, Nicholas and Li, Pinghua and Dedow, Lauren and Chen, Charles and So, Yoon-Sup and Kremling, Karl and Bradbury, Peter J. and et al.}, year={2015}, month={Jun}, pages={575–583} } @misc{brewbaker_kim_so_logrono_moon_ming_lu_josue_2011, title={General Resistance in Maize to Southern Rust (Puccinia polysora Underw.)}, volume={51}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2010.06.0327}, abstractNote={ABSTRACTSouthern corn rust (Puccinia polysora Underw.) is a major tropical disease that can lead to severe yield losses in the tropics. Occasionally it becomes of concern in temperate regions, as in 2010. We summarize 45 yr of research on the occurrence, genetic basis, and breeding of general resistance. Trials were conducted in Colombia, Hawaii, Nigeria, the Philippines, Texas, and Thailand. Temperate maize proved uniformly susceptible. No racially specific monogenes were effective. Resistance varied continuously among tropical inbreds and many of these showed stable intermediate tolerance. Two diallel populations revealed high correlations of inbred values with hybrid array means and slight heterosis for resistance. Narrow‐sense heritabilities were 51% and 66%, and mean square ratios for general to specific combining ability (GCA:SCA) were 7.8 and 10.7 to 1. Generation mean analyses were performed on six sets of families. Mean and additive effects were significant across families, while significant nonadditive effects were rare. Heritability values ranged from 19% to 49%. A set of recombinant lines segregated a primary susceptibility locus on chromosome 6. Studies of 137 near‐isogenic inbred lines (NILs) of resistant tropical inbred Hi27 revealed a dominant susceptibility quantitative trait locus (QTL) in the NIL for dwarf‐1 locus, but linkage could not be confirmed. Premature senescence was associated with rust infections in many NILs, emphasizing the ubiquity of modifying genes. No correlation existed between resistance to southern and common rusts. Resistant tropical inbreds and populations were bred to serve as sources for future improvement.}, number={4}, journal={CROP SCIENCE}, author={Brewbaker, James L. and Kim, Soon Kwon and So, Yoon Sup and Logrono, Manuel and Moon, Hyeon Gui and Ming, Reiguang and Lu, Xiao Wu and Josue, Aleksander D.}, year={2011}, month={Jul}, pages={1393–1409} } @article{so_edwards_2011, title={Predictive Ability Assessment of Linear Mixed Models in Multienvironment Trials in Corn}, volume={51}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2010.06.0338}, abstractNote={ABSTRACTPrediction of future performance of cultivars is an important objective of multienvironment trials (MET). A series of linear mixed models with varying degrees of heterogeneous genotypic variance, correlation, and error variance structure were compared for their ability to predict performance in an untested environment in 51 data sets from the Iowa Crop Performance Test for corn (Zea mays L.). In most cases there was no substantial improvement in predictions among models that included heterogeneity of genotypic variance–covariance components, but the best prediction model included heterogeneous environment‐specific error variances in 63% of data sets analyzed. The largest differences in predictive ability among models appeared to be due to poor estimation of genotypic covariance components in data sets with few common hybrids across 2 yr in a data set. Simulation confirmed the observation from cross validation. Our results suggested that predictions were not improved by modeling heterogeneous genotypic covariance components because of the small number of common hybrids across years. Inclusion of heterogeneous error variances did lead to slight improvements in predictions.}, number={2}, journal={CROP SCIENCE}, author={So, Yoon-Sup and Edwards, Jode}, year={2011}, month={Mar}, pages={542–552} } @article{so_ji_brewbaker_2010, title={Resistance to corn leaf aphid (Rhopalosiphum maidis Fitch) in tropical corn (Zea mays L.)}, volume={172}, ISSN={["1573-5060"]}, DOI={10.1007/s10681-009-0044-z}, number={3}, journal={EUPHYTICA}, author={So, Yoon-Sup and Ji, Hee Chung and Brewbaker, James L.}, year={2010}, month={Apr}, pages={373–381} }