Abstract

Agronomic potential of traditional sunflower spring varieties is low because their flowering and grain filling are often exposed to mid and end-season drought. To overcome this, new breeding strategy consisted of selecting varieties tolerant to winter cold in order to shift to autumn or early winter planting. Nowadays, ‘Ichraq’ is the only registered autumn variety in Morocco. The objective of this research was to evaluate various genotypes selected in different environments under autumn planting conditions. This germplasm was planted early during winter in 2014 at ‘Annoceur’, a mountain site known for its pronounced winter cold. Morphological, physiological, agronomic and technological parameters were considered for the germplasm assessment. Analysis of variance showed significant differences between genotypes for most of these parameters. Plantlet initial vigor average was 3.5 varying from 1 for genotype M32 to 5 for AN8. Leaf area average was 162 cm² varying from 25 to 375 cm² for genotypes M17 and AN34, respectively. Total chlorophyll content average was 43 mg/g, varying from 28 to 79 mg/g for genotypes K7 and M29, respectively. Number of days from sowing to flowering varied from 162 for genotype AN21 to 180 for genotypes M27 and M29. Mean seed yield per plant was 49 g, with a large variation from 8 to 110 g for M18 and K8, respectively. Mean seed oil content was 36%, ranging from 22% for M8 to 47% for K4. Plants exhibiting more performance than ‘Ichraq’ were selected to develop new sunflower germplasm suitable for autumn or early winter sowing. 

Key words: Sunflower, genetic variability, autumn sowing, cold tolerance, physiological and agronomical traits.