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Yang J.,North Dakota State University | Carena M.J.,North Dakota State University | Uphaus J.,Agreliant Genetics LLC
Crop Science | Year: 2010

Maize (Zea mays L.) hybrids with fast field dry down are economically desirable across production regions. However, accurately measuring this genetically complex trait in a simple way has been a challenge to maize breeders. The objective of this research was to propose and test an efficient, simple, and reliable procedure to select genotypes with fast dry down in maize. Area under the dry down curve (AUDDC), an index representing the dynamic progress of field dry down, was proposed. The main experiment included 144 hybrids arranged in a partially balanced lattice design across four short-season environments in North Dakota. Data collected were silking date, ear moisture at four 7-d intervals starting 45 d after pollination, harvest moisture, test weight, and grain yield. Results showed significant genotype × environment interaction for most traits including AUDDC. However, AUDDC had the largest broad-sense heritability (H) among traits (0.84), suggesting it can be effectively utilized to identify faster drier inbred lines and hybrids. Strong correlations were found between AUDDC and silking date, AUD and moisture content at physiological maturity, and AUDDC and harvest moisture. Area under the dry down curve is proposed as an indirect measurement for dry down rate and we encourage its use to develop lines and hybrids with faster dry down. © Crop Science Society of America.

Generation means and heritability analyses were conducted to estimate dominance, additive, maternal and gene interaction effects controlling eleven agronomic characteristics related with production in the pea. Ten generations (P1, P2, F1, F2, RC1, RC2 and each reciprocal generation) from a cross between the Santa Isabel and WSU 31 varieties were sown in two different environments for the present study. Eleven characteristics were evaluated: the time between sowing and flowering (I), the time between sowing and pod formation in the first reproductive node (FPod) and the height of the first reproductive node (H1RN), which were used as earliness indicators; as components of yield, the number of pods per plant (PxP), number of seeds per plant (SxP), number of seeds per pods (SxPod) and 100-seed weight (W100) were evaluated; and as variables associated to the yield, the pod width (PW), pod length (PL), lateral branch number (LBN) and plant height (PH) were evaluated. The results did not show maternal gene effects for the evaluated traits; environmental effects were found in PxP, SxP, SxPod, SFl, FPod and PL; genotype x environment effects were found in PW and W100. All characteristics except SxP and PxP had additive gene effects. The results showed that W100, PW and PL were the characteristics with the highest values for selection.

Orsini E.,University of Hohenheim | Krchov L.M.,University of Hohenheim | Uphaus J.,Agreliant Genetics LLC | Melchinger A.E.,University of Hohenheim
Euphytica | Year: 2012

The European corn borer (ECB, Ostrinia nubilalis Hübner) is a major pest of maize (Zea mays L.) in North America and Europe. In this study, we mapped and characterized QTL affecting the resistance to the first (ECB1) and second generation (ECB2) of ECB and plant height with the aid of 164 SNP and 88 SSR markers. A total of 144 testcross (TC) progenies of double haploid (DH) lines developed from a cross of two parental lines from the Stiff Stalk germplasm pool were tested at six different locations in the USA under both natural and artificial infestation with ECB larvae. Resistance to ECB1 and ECB2 was assessed by measuring leaf feeding and stalk breakage, respectively, using a visual rating scale from 1 (severe damage) to 9 (no damage). Genotypic variance among the TC progenies was significant for all traits. Heritabilities were moderately high (0.69) for stalk breakage and plant height (0.75), but only moderate for leaf feeding (0.43). For stalk breakage, three QTL were detected that together explained 36% of the genetic variance, whereas for leaf feeding only one QTL was mapped, which explained 25% of the genotypic variance. For plant height, two QTL were identified, explaining 20% of the genotypic variance. The QTL for leaf feeding and stalk breakage mapped by us were located in chromosomal regions adjacent to those reported for other maize germplasm and therefore might be suitable candidates for marker-assisted selection (MAS) during line development. © 2011 Springer Science+Business Media B.V.

Piepho H.P.,University of Hohenheim | Ogutu J.O.,University of Hohenheim | Schulz-Streeck T.,University of Hohenheim | Estaghvirou B.,University of Hohenheim | And 2 more authors.
Crop Science | Year: 2012

Computational efficiency of procedures for genomic selection is an important issue when cross-validation is used for model selection and evaluation. Moreover, limited computational resources may be a bottleneck when processing large datasets. This paper reviews several options for computing ridge-regression best linear unbiased prediction (RR-BLUP) in genomic selection and compares their computational efficiencies when using a mixed model package. Attention is also given to the problem of singular genetic variance-covariance. Annotated code is provided for implementing and evaluating the methods using the MIXED procedure of SAS. It is concluded that a recently proposed method based on a spectral decomposition of the variance- covariance matrix of the data is preferable compared to established methods because of its superior computational efficiency and applicability also for singular genetic variance-covariance. © Crop Science Society of America.

Agreliant Genetics Llc | Date: 2013-04-11

Agricultural seeds, namely, soybeans.

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