In Chile, durum wheat is cultivated in high-yielding Mediterranean environments, therefore breeding programs have selected cultivars with high yield potential in addition to grain quality. The genetic progress in grain yield (GY) between 1964 and 2010 was 72.8 kg ha⁻¹ per year. GY showed a positive and significant correlation with days to heading, kernels per unit ground area and thousand kernel weight. The gluten and protein content tended to decrease with the year of cultivar release. The correlation between the δ¹³C of kernels and GY was negative and significant (−0.62, p < 0.05, for all cultivars; and −0.97, p < 0.001, excluding the two oldest cultivars). The yield progress (genetic plus agronomic improvements) of a set of 40–46 advanced lines evaluated between 2006 and 2015 was 569 kg ha⁻¹ per year. Unlike other Mediterranean agro-environments, a longer growing cycle together with taller plants seems to be related to the increase in the GY of Chilean durum wheat during recent decades.

The onset and rate of senescence influence key agronomical traits, including grain yield (GY). Our objective was to assess the relationships between stay-green and GY in a set of fourteen spring bread wheat (Triticum aestivum L.) genotypes with contrasting tolerance to water stress. Based on leaf chlorophyll content index (Chl) and normalized vegetation index (NDVI) measurements, the senescence dynamics at leaf and canopy levels, respectively, were quantified. Parameters describing the dynamics of senescence were examined in glasshouse and field experiments under well-watered (WW) and water-limited (WL) regimes, and they included the following stay-green traits: maximum NDVI or Chl near to anthesis (NDVI_max, Chl_max), the senescence rate (SR, rate), the area under curve (Area_NDVI, Area_Chl), and the time from anthesis to 10 (t_onset), 50 (t₅₀, X₅₀) and 90% (t₉₀) senescence. Our results revealed that specific stay-green traits were significantly different among genotypes and water regimes in both glasshouse and field experiments. GY was positively correlated with t_total (0.42), t_onset (0.62) and NDVI_dif (0.63). Under WL, NDVI_dif and NDVI_max correlated with GY (0.66–0.58), but only t₅₀ correlated with GY under WW (0.62), indicating that phenotyping of stay-green trait is a useful tool for tracking the dynamics of senescence in WW and WL environments.

Canopy temperature (Tc) by thermal imaging is a useful tool to study plant water status and estimate other crop traits. This work seeks to estimate grain yield (GY) and carbon discrimination (Δ¹³C) from stress degree day (SDD = Tc − air temperature, Ta), considering the effect of a number of environmental variables such as the averages of the maximum vapor pressure deficit (VPDmax) and the ambient temperature (Tmax), and the soil water content (SWC). For this, a set of 384 and a subset of 16 genotypes of spring bread wheat were evaluated in two Mediterranean-climate sites under water stress (WS) and full irrigation (FI) conditions, in 2011 and 2012, and 2014 and 2015, respectively. The relationship between the GY of the 384 wheat genotypes and SDD was negative and highly significant in 2011 (r² = 0.52 to 0.68), but not significant in 2012 (r² = 0.03 to 0.12). Under WS, the average GY, Δ¹³C, and SDD of wheat genotypes growing in ten environments were more associated with changes in VPDmax and Tmax than with the SWC. Therefore, the amount of water available to the plant is not enough information to assume that a particular genotype is experiencing a stress condition.

Phytoene synthase 1 (Psy1) and lipoxygenase 1 (Lpx-1) are key genes involved in the synthesis and catalysis of carotenoid pigments in durum wheat, regulating the increase and decrease in these compounds, respectively, resulting in the distinct yellow color of semolina and pasta. Here, we reported new haplotype variants and/or allele combinations of these two genes significantly affecting yellow pigment content in grain and semolina through their effect on carotenoid pigments. To reach the purpose of this work, three complementary approaches were undertaken: the identification of QTLs associated to carotenoid content on a recombinant inbred line (RIL) population, the characterization of a Mediterranean panel of accessions for Psy1 and Lpx-1 genes, and monitoring the expression of Psy1 and Lpx-1 genes during grain filling on two genotypes with contrasting yellow pigments. Our data suggest that Psy1 plays a major role during grain development, contributing to semolina yellowness, and Lpx-1 appears to be more predominant at post-harvest stages and during pasta making.

Intercropping could increase the capacity of crops to use soil resources. The aim of this study was to investigate the effects of lupin/wheat intercropping on soil properties, grain yield and nutrient uptake at different plant densities. Lupin and wheat were grown under field conditions as monocrops and intercrops. Soil nutrient availability and relative abundance of functional genes (acdS, phoD, phoC and nifH) were evaluated. The results obtained indicate that the cropping system had a significant effect (p < 0.001) on N and P availability. Lupin monocrop led to significantly higher N availability compared to intercrop. Intercropping resulted in significantly lower Olsen-P and K in soil concentrations compared to monocropping. No significant differences were observed in enzyme activity, except for phosphatase, which was 152% greater in the treatments at high plant density. Foliar nutrients were significantly higher in intercropping compared to monocropping. Acid phosphatase gene phoC was more abundant than the alkaline phosphatase gene phoD, which plays a more relevant role in acidic Andisols. The results confirm that N and P mobilization can improve nutrient absorption on wheat. When intercropped, lupin had positive effects on wheat due to its P mobilization capacity, while no effects were observed on lupin.

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.