Christian Alfaro

Quinoa (Chenopodium quinoa Willd.) is a genetically diverse crop that has gained popularity in recent years due to its high nutritional content and ability to tolerate abiotic stresses such as salinity and drought. Varieties from the coastal lowland ecotype are of particular interest due to their insensitivity to photoperiod and their potential to be cultivated in higher latitudes. We performed a field experiment in the southern Atacama Desert in Chile to investigate the responses to reduced irrigation of nine previously selected coastal lowland self-pollinated (CLS) lines and the commercial cultivar Regalona. We found that several lines exhibited a yield and seed size superior to Regalona, also under reduced irrigation. Plant productivity data were analyzed together with morphological and physiological traits measured at the visible inflorescence stage to estimate the contribution of these traits to differences between the CLS lines and Regalona under full and reduced irrigation. We applied proximal sensing methods and found that thermal imaging provided a promising means to estimate variation in plant water use relating to yield, whereas hyperspectral imaging separated lines in a different way, potentially related to photosynthesis as well as water use.

This study analysed the effect of flowering time as influenced by photoperiod sensitivity genes on yield and yield stability in durum wheat. Twenty-three spring genotypes harbouring different allele combinations at Ppd-A1 and Ppd-B1 were grown in 15 field experiments at three sites at latitudes from 41° to 19° N (Spain, Mexico-North and Mexico-South). Low temperature and solar radiation before flowering and long day length during grain-filling characteristic for the Spanish site resulted in high grain number/m² (GN) and yield (GY), while a moderate GN combined with high solar radiation during grain-filling at Mexico-North led to heavier grains. Allele combination GS100-Ppd-A1a/Ppd-B1a reduced the flowering time up to nine days when compared with Ppd-A1b/Ppd-B1a. Differences in flowering time caused by Ppd-A1/Ppd-B1 allele combinations did not affect yield. Combinations GS105-Ppd-A1a/Ppd-B1b and Ppd-A1b/Ppd-B1b resulted in the highest GN, linked to spikelets/spike, which was higher in GS105-Ppd-A1a/Ppd-B1b due to more grains/spikelet. Flowering time caused by Eps had a minor effect on GN, spikes/m² and grains/spike, but late flowering resulted in reduced grain weight and GY. Allele combinations harbouring alleles conferring a similar photoperiod sensitivity response at Ppd-A1 and Ppd-B1 resulted in greater yield stability than combinations that carry alleles conferring a different response. Allele combination GS100-Ppd-A1a/Ppd-B1a was the most suitable in terms of yield and yield stability of durum wheat cultivated under irrigation within the studied latitudes.