Context: Genetically heterogeneous materials of inbred crops, such as evolutionary populations (EPs) and line mixtures, could reduce the genetic erosion and increase the yield stability of crops. EPs may also be exploited for bulk-based selection of inbred lines as an alternative to single-seed descent (SSD)-derived lines. Objective: This study focused on pea to compare: (a) biparental EPs from three connected crosses and their combination, and their bulk-derived inbred lines and 6-line and 12-line static mixtures, for grain yield, yield stability, and reliability (which combines mean yield and yield stability); (b) bulk-based vs. SSD-based selection of inbred lines. Methods: Bulk-derived lines were mass-selected after four-year natural selection and underwent further multi-environment selection of elite lines and components of mixtures. EPs, selected bulk-derived lines, and static mixtures were evaluated across eight environments of Northern and Central Italy encompassing organic or conventional management and pure stand or intercropping with cereals. Bulk-based vs. SSD-based selection of inbred lines were compared across three environments. Farmers’ acceptability and various adaptive traits were also recorded. We also assessed shifts for adaptive traits between EPs or derived lines for the target region and material selected for a non-target region featuring severe terminal drought. Results: In a comparison based on best-performing material, a 6-line mixture exhibited 4–7 % greater yield or yield reliability, and EP material showed a modest penalty (actually nil in its area of initial development), compared with bulk-derived lines. Most of this material tended towards greater yield, yield stability and reliability (in a context of large genotype × environment interaction), competitive ability in intercropping and farmers’ appreciation than the best-performing commercial cultivar. Bulk-derived lines displayed 24 % higher mean yield, 2.3–2.5 greater yield gain per selection cycle and greater farmers’ acceptability than SSD-derived lines, and were the only lines that allowed for genetic progress over commercial cultivars. Their advantage was associated with greater tolerance to low winter temperatures and taller plant stature that favored their adaptation to intercropping or organic farming. The EPs selected in contrasting environments or their derived lines displayed rapid shifts in adaptation pattern and associated traits. Conclusions: Evolutionary breeding issued highly valuable populations, inbred lines and line mixtures. EPs displayed quick adaption to specific environments for a low selection cost. Implications: Our results have implications for small and large breeding programs, to increase the efficiency of phenotypic selection and favor the optimal integration of genomic selection
Value of heterogeneous material and bulk breeding for inbred crops: A pea case study
Russi L.;
2023
Abstract
Context: Genetically heterogeneous materials of inbred crops, such as evolutionary populations (EPs) and line mixtures, could reduce the genetic erosion and increase the yield stability of crops. EPs may also be exploited for bulk-based selection of inbred lines as an alternative to single-seed descent (SSD)-derived lines. Objective: This study focused on pea to compare: (a) biparental EPs from three connected crosses and their combination, and their bulk-derived inbred lines and 6-line and 12-line static mixtures, for grain yield, yield stability, and reliability (which combines mean yield and yield stability); (b) bulk-based vs. SSD-based selection of inbred lines. Methods: Bulk-derived lines were mass-selected after four-year natural selection and underwent further multi-environment selection of elite lines and components of mixtures. EPs, selected bulk-derived lines, and static mixtures were evaluated across eight environments of Northern and Central Italy encompassing organic or conventional management and pure stand or intercropping with cereals. Bulk-based vs. SSD-based selection of inbred lines were compared across three environments. Farmers’ acceptability and various adaptive traits were also recorded. We also assessed shifts for adaptive traits between EPs or derived lines for the target region and material selected for a non-target region featuring severe terminal drought. Results: In a comparison based on best-performing material, a 6-line mixture exhibited 4–7 % greater yield or yield reliability, and EP material showed a modest penalty (actually nil in its area of initial development), compared with bulk-derived lines. Most of this material tended towards greater yield, yield stability and reliability (in a context of large genotype × environment interaction), competitive ability in intercropping and farmers’ appreciation than the best-performing commercial cultivar. Bulk-derived lines displayed 24 % higher mean yield, 2.3–2.5 greater yield gain per selection cycle and greater farmers’ acceptability than SSD-derived lines, and were the only lines that allowed for genetic progress over commercial cultivars. Their advantage was associated with greater tolerance to low winter temperatures and taller plant stature that favored their adaptation to intercropping or organic farming. The EPs selected in contrasting environments or their derived lines displayed rapid shifts in adaptation pattern and associated traits. Conclusions: Evolutionary breeding issued highly valuable populations, inbred lines and line mixtures. EPs displayed quick adaption to specific environments for a low selection cost. Implications: Our results have implications for small and large breeding programs, to increase the efficiency of phenotypic selection and favor the optimal integration of genomic selectionI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
