Mapping of QTLs for leaf area and the association with winter hardiness in fall-sown lentil

Variations in plant architecture are often associated with the ability of plants to survive cold stress during winter. In studies of winter hardiness in lentil, it appeared that small leaf area was associated with improved winter survival. Based on this observation, the inheritance of leaf area and the relationship with winter hardiness using an F6 - derived recombinant inbred line (RIL) population from the cross of WA8649090 x Precoz was investigated. The WA8649090 parent was winter hardy and had small leaves, while the Precoz parent was non-winter hardy and had large leaves. The 106 RILs and the parents were planted in a field in a randomized complete block design with three replications. Leaf area(cm2) of leaves from the fourth node was measured using a flatbed scanner and WinRHIZO software. Average leaf area for WA8649090 was 0.46 cm2, while leaf area for Precoz was 0.89 cm2. Average leaf area of the RILs was 0.63 cm2, and the frequency distribution was continuous, indicating the effects of more than one gene. Quantitative trait locus (QTL) analysis using a 130-point linkage map revealed one major QTL on linkage group 6 which explained 20.45% of the phenotypic variation for leaf area. The location of QTL for leaf area mapped the same region where one of the QTL for winter hardiness was mapped and significant association (r2 = 0.750, P< 0.01) was found between leaf area and winter hardiness. These results indicated an association between winter hardiness and leaf area that provides information applicable to lentil breeding.Keywords: Leaf area, lentil, recombinant inbred line (RIL), QTL mapping, winter hardines

Genomics-assisted breeding in four major pulse crops of developing countries: present status and prospects

The global population is continuously increasing and is expected to reach nine billion by 2050. This huge population pressure will lead to severe shortage of food, natural resources and arable land. Such an alarming situation is most likely to arise in developing countries due to increase in the proportion of people suffering from protein and micronutrient malnutrition. Pulses being a primary and affordable source of proteins and minerals play a key role in alleviating the protein calorie malnutrition, micronutrient deficiencies and other undernourishment-related issues. Additionally, pulses are a vital source of livelihood generation for millions of resource-poor farmers practising agriculture in the semi-arid and sub-tropical regions. Limited success achieved through conventional breeding so far in most of the pulse crops will not be enough to feed the ever increasing population. In this context, genomics-assisted breeding (GAB) holds promise in enhancing the genetic gains. Though pulses have long been considered as orphan crops, recent advances in the area of pulse genomics are noteworthy, e.g. discovery of genome-wide genetic markers, high-throughput genotyping and sequencing platforms, high-density genetic linkage/QTL maps and, more importantly, the availability of whole-genome sequence. With genome sequence in hand, there is a great scope to apply genome-wide methods for trait mapping using association studies and to choose desirable genotypes via genomic selection. It is anticipated that GAB will speed up the progress of genetic improvement of pulses, leading to the rapid development of cultivars with higher yield, enhanced stress tolerance and wider adaptability

Chickpea

The narrow genetic base of cultivated chickpea warrants systematic collection, documentation and evaluation of chickpea germplasm and particularly wild Cicer species for effective and efficient use in chickpea breeding programmes. Limiting factors to crop production, possible solutions and ways to overcome them, importance of wild relatives and barriers to alien gene introgression and strategies to overcome them and traits for base broadening have been discussed. It has been clearly demonstrated that resistance to major biotic and abiotic stresses can be successfully introgressed from the primary gene pool comprising progenitor species. However, many desirable traits including high degree of resistance to multiple stresses that are present in the species belonging to secondary and tertiary gene pools can also be introgressed by using special techniques to overcome pre- and post-fertilization barriers. Besides resistance to various biotic and abiotic stresses, the yield QTLs have also been introgressed from wild Cicer species to cultivated varieties. Status and importance of molecular markers, genome mapping and genomic tools for chickpea improvement are elaborated. Because of major genes for various biotic and abiotic stresses, the transfer of agronomically important traits into elite cultivars has been made easy and practical through marker-assisted selection and marker-assisted backcross. The usefulness of molecular markers such as SSR and SNP for the construction of high-density genetic maps of chickpea and for the identification of genes/QTLs for stress resistance, quality and yield contributing traits has also been discussed

Predicting the Personal-Best Times of Speed Skaters Using Case-Based Reasoning

Speed skating is a form of ice skating in which the skaters race each other over a variety of standardised distances. Races take place on specialised ice-rinks and the type of track and ice conditions can have a significant impact on race-times. As race distances increase, pacing also plays an important role. In this paper we seek to extend recent work on the application of case-based reasoning to marathon-time prediction by predicting race-times for speed skaters. In particular, we propose and evaluate a number of case-based reasoning variants based on different case and feature representations to generate track-specific race predictions. We show it is possible to improve upon state-of-the-art prediction accuracy by harnessing richer case representations using shorter races and track-adjusted finish and lap-times.</p