Summary: Aegilops tauschii is the diploid progenitor of the wheat D subgenome and a valuable resource for wheat breeding, yet, genetic analysis of resistance against Fusarium head blight (FHB) and the major Fusarium mycotoxin deoxynivalenol (DON) is lacking. We treated a panel of 147 Ae. tauschii accessions with either Fusarium graminearum spores or DON solution and recorded the associated disease spread or toxin‐induced bleaching. A k‐mer‐based association mapping pipeline dissected the genetic basis of resistance and identified candidate genes. After DON infiltration nine accessions revealed severe bleaching symptoms concomitant with lower conversion rates of DON into the non‐toxic DON‐3‐O‐glucoside. We identified the gene AET5Gv20385300 on chromosome 5D encoding a uridine diphosphate (UDP)‐glucosyltransferase (UGT) as the causal variant and the mutant allele resulting in a truncated protein was only found in the nine susceptible accessions. This UGT is also polymorphic in hexaploid wheat and when expressed in Saccharomyces cerevisiae only the full‐length gene conferred resistance against DON. Analysing the D subgenome helped to elucidate the genetic control of FHB resistance and identified a UGT involved in DON detoxification in Ae. tauschii and hexaploid wheat. This resistance mechanism is highly conserved since the UGT is orthologous to the barley UGT HvUGT13248 indicating descent from a common ancestor of wheat and barley.

In the maize producing regions of Sub-Saharan Africa (SSA), compounding effects of genotype-by-environment interaction have necessitated breeding maize for outstanding performance and stability across varying environments. This study was conducted to assess the performance and stability of late-maturing cultivars and their respective hybrids evaluated under contrasting environments in the tropical rainforest region. We evaluated 108 genotypes in field trials under three different growing conditions in 2018 involving 14 open-pollinated parents and their hybrids derived from a diallel mating design. The genotypes were evaluated under field conditions using 9 × 12 alpha lattice design with three replications in six environments. The genotypes were divided into three groups, containing either the parents, hybrids or checks, for estimating the stability variance and grain yield. The difference between the lowest and highest yielding environment was 3.9 t ha⁻¹, while the repeatability of the grain yield trials ranged from 39 to 80%. The average grain yield of the hybrids (2.33 t ha⁻¹) was significantly higher than that of the parents (2.19 t ha⁻¹) and the check varieties (2.03 t ha⁻¹). The hybrids were more stable than both the parents and the checks. They also showed a higher stability against a common group of the parents and checks. The results of this study suggest that high yielding and stable population hybrids can be utilized in breeding programmes aiming to provide improved varieties for the large number of rural maize farmers in the SSA zone, who often lack access or the capacity to purchase commercial hybrids.

Rising temperatures can affect stomatal and nonstomatal control over photosynthesis, through stomatal closure in response to increasing vapor pressure deficit (VPD), and biochemical limitations, respectively. To explore the independent effect...

Plant breeding experiments require the use of appropriate experimental designs that will efficiently block variation due to wide heterogeneity nature of tropical soils. The primary objective of this study was to assess the effectiveness of eight different alpha-lattice designs relative to randomized complete block design for evaluating 108 genotypes of maize under rainforest agro-ecology. The maize genotypes were field-tested using three replications at two locations. Data were collected on grain yield and other agronomic traits. Data collected were subjected to analysis of variance (ANOVA) assuming randomized complete block design (RCBD) and eight alpha-lattice designs. Pearson's correlation and stepwise multiple regression analyses were used to analyze relationship among different designs and efficiency of the lattice designs over RCBD was computed. Result showed that all the alpha lattice designs except 27 × 4 were effective in evaluating the genotypes for plant height. There was significant difference (p < 0.001) among genotypes for grain yield only when data were analyzed based on 9 × 12 alpha lattice design. In addition, results showed that the proportion of variation due to blocking and R-square values of the model increased with increase in the number of blocks for grain yield. In contrast, coefficient of variation decreased with increase in the number of blocks. The result showed an increase in efficiency of the alpha lattice designs as the number of blocks increased. It could then be concluded that the more the number of blocks within replicate, the proportion of total variation due to blocking increased, the coefficient of variation (CV) reduced, coefficient of determination (R-square) increased and thus, effectiveness increased. Appropriateness of designs was trait dependent. The 9 × 12 alpha lattice design was identified to be the best in the evaluation of grain yield for the maize genotypes.

The genetic variability and inter-relationships between yield and associated traits in some taro (Colocasia esculenta (L.) Schott) genotypes were investigated in two years across two locations. The experiment was laid out as randomized complete block design with three replications in each location. Data were collected on the growth and yield attributes of taro. The genetic variability of the attributes measured in both locations was studied to estimate the genotypic (GCV) and phenotypic (PCV) coefficients of variation, broad sense heritability (h²b) and genetic advance (GA). Considering GCV, h²b and GA simultaneously as the best estimators of the amount of advance expected from selection, number of secondary shoots/plant and number of leaves/plant gave the highest values in each of the locations. This shows that a satisfactory selection program for improvement of these genotypes through these traits is possible at each specific location. Correlation analysis showed that all the traits measured were significantly and positively correlated with taro yield except corm and cormel lengths. Number of cormels/plant had the strongest positive correlation with taro yield (r = 0.699**) followed by cormel weight (r = 0.624**). Path-coefficient analysis and stepwise multiple regression analysis revealed cormel weight and number of cormels/plant as the biggest determinants of taro yield, both contributing about 72% of the total variation in yield. This suggests that these two characters are important selection indices for taro yield improvement.