Genotype selection for physiological responses of drought tolerance using molecular markers in polycross hybrids of orchardgrass

Abstract

The present study aimed to assess the effect of contrasting levels of molecular and phenotypic diversity among polycross parents of orchardgrass on the performance of synthetic progeny with respect to physiological responses and drought tolerance. Four polycross groups each composed of six parental plants were evaluated under normal irrigation and drought stress conditions. A number of 923 inter simple sequence repeats and sequence related amplified polymorphism markers and several phenotypic traits were used to select contrasting levels of diversity (high and low) in parental genotypes. Highly significant correlation was observed between molecular distance and progeny performances at both normal irrigation and drought stress conditions. High molecular diversity among polycross parents led to a significant yield advantage of first generation progeny with averages of 34.40% for normal irrigation and 48.10% for drought stress conditions. Also crosses between genetically distant parents produced progeny with considerable drought tolerance and yield stability. Positive associations between phenotypic distance of parents and progeny performance were found for most physiological traits at both moisture regimes but phenotypic distances had weak association with forage yield, stress tolerance index and yield stability of progeny. Significant associations between drought tolerance index and some physiological traits confirmed the importance of these traits in conferring drought tolerance of orchardgrass. Our results underscore the effectiveness of marker‐assisted polycross breeding to improve drought tolerance and yield stability through physiological traits in orchardgrass.

Variation in persistency, postdrought recovery and root characteristics in a tall fescue germplasm under interactive effects of exogenously applied salicylic acid and water stress

“…The positive correlation between DFY and STI under mild and intense drought stress indicated that selection based on higher STI would lead to genotypes with higher yield and drought tolerance. Stability of production is one of the main breeding objectives in breeding for stress environments in perennial grasses (Abtahi et al., 2019). However, a negative relationship was found between STI and PE under mild and intense drought stress.…”

Genetic diversity analysis in wheat cultivars using SCoT and ISSR markers, chloroplast DNA barcoding and grain SEM

“…In the current study, a higher level of polymorphism ranging between 11 and 88%, with an average of 51.4%, was recorded using 12 primers in the global 12 examined wheat cultivars. In this connection, about 923 ISSR and sequence-related amplified polymorphism (SRAP) molecular markers, besides numerous phenotypic traits were employed to monitor triggered improvement of orchadgrass polycross populations subjected to water deficit conditions [ 24 , 25 ].…”

“…SCoT uses a single 18-mer primer in a polymerase chain reaction (PCR) assays and requires an annealing temperature of 50 °C [ 14 ]. The ISSR and SCoT polymorphism has been used in genetic resource differentiation, cultivar characterization, and marker-assisted breeding programs in many plants; examples include alfalfa and Egyptian clover [ 15 ], Nigella sativa [ 16 ], Medicago sativa [ 17 ], Pistacia lentiscus [ 18 ], Moringa oleifera [ 19 ], Lathyrus species [ 20 ], Crepidium acuminatum [ 21 ], maize [ 22 ], Hordeum [ 23 ], and smooth bromegrass [ 24 , 25 ].…”