Variety selection in perennial pasture crops involves identifying best varieties from data collected from multiple harvest times in field trials. For accurate selection, the statistical methods for analysing such data need to account for the spatial and temporal correlation typically present. This paper provides an approach for analysing multi-harvest data from variety selection trials in which there may be a large number of harvest times. Methods are presented for modelling the variety by harvest effects while accounting for the spatial and temporal correlation between observations. These methods provide an improvement in model fit compared to separate analyses for each harvest, and provide insight into variety by harvest interactions. The approach is illustrated using two traits from a lucerne variety selection trial. The proposed method provides variety predictions allowing for the natural sources of variation and correlation in multi-harvest data.
Aluminium (Al) phytotoxicity is one of the major constraints for barley (Hordeum vulgare L.) production on acid soils. Genetic variation for Al tolerance is present in barley germplasm. Previous studies have shown that Al tolerance in cv. Dayton and WB229 is controlled by a single locus on 4H. The present study was conducted to investigate the genetic control of Al tolerance in Japanese barley cv. Honen, and validate the linkage relationship between the Al tolerance locus and the molecular markers established previously. An F3 progeny representing 94 F2s from the cross of F6ant28B48-16 (Al sensitive) × Honen (Al tolerant) was evaluated for Al tolerance by staining roots with eriochrome cyanine R. A single Al tolerance locus Alt was validated on the long arm of chromosome 4H in Honen. Single sequence repeat (SSR) markers Bmag353 and HVM68 flanked the Alt locus at a distance of 1.6 ± 0.9 and 5.1 ± 1.7 cM, respectively. Our results have shown that the linkage between SSR markers and the Al tolerance locus can be used to characterise the ‘unknown source’ for Al tolerance.
Temperate japonica rice (Oryza sativa) is usually grown in temperate regions. When grown in tropical areas, most temperate japonica rice plants flower prematurely and do not show sufficient vegetative growth. Fourteen japonica rice varieties and lines adapting to tropical environments were developed in the Philippines (tropical Asia) between 2008 and 2014. Their genomes were characterized by genomewide single nucleotide polymorphism genotyping, and their grain yields were examined in the Philippines during the wet and dry seasons and in a high-altitude area of Burundi (tropical Africa). Based on the genotyping, all 14 materials were found to belong to the temperate japonica rice group. Grain yields were more affected by the environment than by the genotypes. Two of the fourteen rice materials showed more stable and higher yields than the check varieties across the three environments, and one of the two has been released as a commercial variety in the Philippines.Together, these results demonstrate that rice plants genetically belonging to the temperate japonica group can be bred to adapt to tropical areas.
Experiments with wheat anther culture were conducted with the aim of assembling a workable system for doubled-haploid production for Australian wheat breeding. One Australian cultivar, Grebe, carrying the 1BL/1RS translocation was particularly responsive. A modified C17 medium was developed which proved effective when solidified with agarose or when used as a liquid in conjunction with membrane support rafts. The membrane rafts have great potential to assist the development of the anther culture procedure since the medium can be rapidly replenished or replaced with minimal disturbance of the tissue.
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