Grain yield and its components study and their association with normalized difference vegetation index (NDVI) under terminal water deficit and well-irrigated conditions in wheat (Triticum durum Desf. and Triticum aestivum L.)

Six genotype of Triticum aestivum L. in 1991 and one genotype of Triticum durum Desf. and three of T. aestivum L. in 1992 were studied under different water regimes: full irrigation (R1), mild water stress (R3) and severe water stress (R2) at Magneraud (France). Traits evaluated were grain yield and its components, stress susceptibility index (SSI) and normalized difference vegetation index (NDVI). The analysis of variance revealed significant differences between regimes and among the cultivars for all traits except between regimes for thousand grains weight in 1991. The regime × variety interaction was significant for grain yield, thousand grains weight and NDVI in 1992 and for grain yield in 1991. For all traits, durum wheat (T. durum Desf.) has higher reduction in the two water stress than the common wheat (T. aestivum L.). Correlations studies revealed that grain yield, grains number/m², thousand grains weight and NDVI were associated with each other except for correlations between thousand grains weight on one hand and grain yield (1992) and grains number/m² (1991) on the other hand. 51.55, 27.88, 4.12% (1991) and 75, 43 and 20.2% (1992) of grain yield, grains/m² and thousand grains weight variability, respectively were explained by means NDVI variability. The grain yield and grains number/m² could be predicted using a single regression with NDVI.Keywords: Grain yield, grain yield components, NDVI, durum wheat and bread wheat

Study of genetic determinism of harvest index in durum wheat (Triticum durum Desf) under semi-arid conditions

Out of six varieties of durum wheat (Triticum durum Desf.), two local varieties with a low harvest index and four others with high harvest indices and short straw imported from France were studied in a diallel cross. The experiment was done in a complete randomized block design with three replications. It was done at the Research Station of the Institute of Technical Big Cultures of Khemis Miliana, located in the semi-arid high Chelif Valley in Algeria. Before spikes emerged from the grains of the six varieties, we did a complete diallel hybridization between them. This resulted in 30 crosses. The heterosis that appeared in F2 of the harvest index in some hybrids is because the genotypes vary. Nefer variety located close to the parabola shows there is no transgression in character. The effects of additive are confirmed by the Hayman analysis in the harvest index. The most promising breeding stocks that can be used to improve the harvest index of durum varieties are Guem Goum Erkham, Hedba3 and Excalibur.Key words: Genetic determinism, Triticum durum Desf, harvest index