EXPERIMENTAL ERROR IN AGRONOMIC FIELD TRIALS

Agronomic experiments often summarize work carried out in trials run in several locations over several years, referred to generically as environments. The appropriate statistical analyses for these experiments depend on definitions used for experimental error. The results of one such experiment, in which identical designs were used in each environment, illustrate the commonalities and differences in analyses that can result from using different definitions of experimental error

Whole-genome scanning for mapping determinacy in Pigeonpea (Cajanus spp.)

Determinacy is an agronomically important trait in several crop species including pigeonpea. With an objective to investigate determinacy in pigeonpea, a set of 94 pigeonpea lines including 11 determinate (DT) and 83 indeterminate (IDT) lines were used for genotyping with DArT arrays (with 6144 features) and 768 SNP markers using GoldenGate assay. The polymorphism information content (PIC) for these markers varied from 0.02 to 0.50. Association analysis on marker genotyping and phenotyping data showed a significant association (P ≤ 0.01) of determinacy with 19 SNP and 6 DArT markers explaining 8.05–8.58% and 7.26–14.53% phenotypic variation, respectively. Clustering based on entire DArT and SNP markers could not discriminate DT lines from IDT lines; however, analysis with associated markers discriminated DT lines from the IDT lines. Marker–trait associations after validation may prove useful in marker-assisted selection (MAS) involving the development of ideal DT genotypes for environments with moderate growth, tolerance to drought and water logging. This is the first report on mapping of determinacy trait as well as the first report on association mapping for any trait in pigeonpea

Genetic and environmental effects on crop development determining adaptation and yield

Slafer, Gustavo Ariel. ICREA - AGROTECNIO - Spain.Kantolic, Adriana Graciela. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.Appendino, María Laura. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.Tranquilli, Gabriela Edith. Instituto Nacional de Tecnología Agropecuaria (INTA). Recursos Naturales. Instituto de Recursos Biológicos. Buenos Aires, Argentina.Miralles, Daniel Julio. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.Savin, Roxana. ICREA - AGROTECNIO - Spain.Crop development is a sequence of phenological events controlled by the genetic background and influenced by external factors, which determines changes in the morphology and/or function of organs (Landsberg, 1977). Although development is a continuous process, the ontogeny of a crop is frequently divided into discrete periods, for instance ‘vegetative’, ‘reproductive’ and ‘grain - filling’ phases (Slafer, 2012). Patterns of phenological development largely determine the adaptation of a crop to a certain range of environments. For example, genetic improvement in grain yield of wheat has been associated with shorter time from sowing to anthesis in Mediterranean environments of western Australia (Siddique et al., 1989), whereas no consistent trends in phenology were found where drought is present but not necessarily terminal, including environments of Argentina, Canada and the USA (Slafer and Andrade, 1989, 1993; Slafer et al., 1994a) (Fig. 12.1). Even in agricultural lands of the Mediterranean Basin where wheat has been grown for many centuries, breeding during the last century did not clearly change phenological patterns (Acreche et al., 2008). This chapter focuses on two major morphologically and hysiologically contrasting grain crops: wheat and soybean. For both species, we have an advanced understanding of development and physiology in general. Wheat is a determinate, long-day grass of temperate origin, which is responsive to vernalization. Soybean is a typically indeterminate (but with determinate intermediate variants), short-day grain legume of tropical origin, which is insensitive to vernalization. Comparisons with other species are used to highlight the similarities and differences. The aims of this chapter are to outline the developmental characteristics of grain crops and the links between phenology and yield, to revise the mechanisms of environmental and genetic control of development and to explore the possibilities of improving crop adaptation and yield potential through the fine-tuning of developmental patterns

Maize hybrid X08C908

A novel maize variety designated X08C908 and seed, plants and plant parts thereof, produced by crossing Pioneer Hi-Bred International, Inc. proprietary inbred maize varieties. Methods for producing a maize plant that comprises crossing hybrid maize variety X08C908 with another maize plant. Methods for producing a maize plant containing in its genetic material one or more traits introgressed into X08C908 through backcross conversion and/or transformation, and to the maize seed, plant and plant part produced thereby. This invention relates to the maize variety X08C908, the seed, the plant produced from the seed, and variants, mutants, and minor modifications of maize variety X08C908. This invention further relates to methods for producing maize varieties derived from maize variety X08C908

Maize hybrid X13C726

A novel maize variety designated X13C726 and seed, plants and plant parts thereof, produced by crossing Pioneer Hi-Bred International, Inc. proprietary inbred maize varieties. Methods for producing a maize plant that comprises crossing hybrid maize variety X13C726 with another maize plant. Methods for producing a maize plant containing in its genetic material one or more traits introgressed into X13C726 through backcross conversion and/or transformation, and to the maize seed, plant and plant part produced thereby. This invention relates to the maize variety X13C726, the seed, the plant produced from the seed, and variants, mutants, and minor modifications of maize variety X13C726. This invention further relates to methods for producing maize varieties derived from maize variety X13C726

Maize hybrid X08F124

A novel maize variety designated X08F124 and seed, plants and plant parts thereof are produced by crossing inbred maize varieties. Methods for producing a maize plant by crossing hybrid maize variety X08F124 with another maize plant are disclosed. Methods for producing a maize plant containing in its genetic material one or more traits introgressed into X08F124 through backcross conversion and/or transformation, and to the maize seed, plant and plant part produced thereby. This invention relates to the maize variety X08F124, the seed, the plant produced from the seed, and variants, mutants, and minor modifications of maize variety X08F124. This invention further relates to methods for producing maize varieties derived from maize variety X08F124

The Soybean Stem Growth Habit Gene Dt1 Is an Ortholog of Arabidopsis TERMINAL FLOWER11[W][OA]

Classical genetic analysis has revealed that the determinate habit of soybean (Glycine max) is controlled by a recessive allele at the determinate stem (Dt1) locus. To dissect the molecular basis of the determinate habit, we isolated two orthologs of pea (Pisum sativum) TERMINAL FLOWER1a, GmTFL1a and GmTFL1b, from the soybean genome. Mapping analysis indicated that GmTFL1b is a candidate for Dt1. Despite their high amino acid identity, the two genes had different transcriptional profiles. GmTFL1b was expressed in the root and shoot apical meristems (SAMs), whereas GmTFL1a was mainly expressed in immature seed. The GmTFL1b transcript accumulated in the SAMs during early vegetative growth in both the determinate and indeterminate lines but thereafter was abruptly lost in the determinate line. Introduction of the genomic region of GmTFL1b from the indeterminate line complemented the stem growth habit in the determinate line: more nodes were produced, and flowering in the terminal raceme was delayed. The identity between Dt1 and GmTFL1b was also confirmed with a virus-induced gene silencing experiment. Taken together, our data suggest that Dt1 encodes the GmTFL1b protein and that the stem growth habit is determined by the variation of this gene. The dt1 allele may condition the determinate habit via the earlier loss in GmTFL1b expression concomitant with floral induction, although it functions normally under the noninductive phase of flowering. An association test of DNA polymorphisms with the stem growth habit among 16 cultivars suggested that a single amino acid substitution in exon 4 determines the fate of the SAM after floral induction