Table_1_Identification of QTLs associated with seed protein concentration in two diverse recombinant inbred line populations of pea.xlsx

Improving the seed protein concentration (SPC) of pea (Pisum sativum L.) has turned into an important breeding objective because of the consumer demand for plant-based protein and demand from protein fractionation industries. To support the marker-assisted selection (MAS) of SPC towards accelerated breeding of improved cultivars, we have explored two diverse recombinant inbred line (RIL) populations to identify the quantitative trait loci (QTLs) associated with SPC. The two RIL populations, MP 1918 × P0540-91 (PR-30) and Ballet × Cameor (PR-31), were derived from crosses between moderate SPC × high SPC accessions. A total of 166 and 159 RILs of PR-30 and PR-31, respectively, were genotyped using an Axiom® 90K SNP array and 13.2K SNP arrays, respectively. The RILs were phenotyped in replicated trials in two and three locations of Saskatchewan, Canada in 2020 and 2021, respectively, for agronomic assessment and SPC. Using composite interval mapping, we identified three QTLs associated with SPC in PR-30 and five QTLs in PR-31, with the LOD value ranging from 3.0 to 11.0. A majority of these QTLs were unique to these populations compared to the previously known QTLs for SPC. The QTL SPC-Ps-5.1 overlapped with the earlier reported SPC associated QTL PC-QTL-3. Three QTLs, SPC-Ps-4.2, SPC-Ps-5.1, and SPC-Ps-7.2 with LOD scores of 7.2, 7.9, and 11.3, and which explained 14.5%, 11.6%, and 11.3% of the phenotypic variance, respectively, can be used for marker-assisted breeding to increase SPC in peas. Eight QTLs associated with the grain yield were identified with LOD scores ranging from 3.1 to 8.2. Two sets of QTLs, SPC-Ps-2.1 and GY-Ps-2.1, and SPC-Ps-5.1 and GY-Ps-5.3, shared the QTL/peak regions. Each set of QTLs contributed to either SPC or grain yield depending on which parent the QTL region is derived from, thus confirming that breeding for SPC should take into consideration the effects on grain yield.

鉴于消费者对植物基蛋白的需求以及蛋白质分馏产业的市场需求，提升豌豆（Pisum sativum L.）的种子蛋白质含量（seed protein concentration, SPC）已成为重要的育种目标。为支撑针对SPC的标记辅助选择（marker-assisted selection, MAS）以加速优良品种的育种进程，我们利用两个多样化的重组自交系（recombinant inbred line, RIL）群体，筛选与SPC相关的数量性状位点（quantitative trait loci, QTLs）。
两个RIL群体分别为MP 1918 × P0540-91（PR-30）与Ballet × Cameor（PR-31），均由中等SPC种质与高SPC种质杂交选育得到。其中PR-30和PR-31群体分别包含166和159个RIL系，分别使用Axiom® 90K单核苷酸多态性（single nucleotide polymorphism, SNP）阵列与13.2K SNP阵列完成基因分型。
2020年与2021年，我们分别在加拿大萨斯喀彻温省的2个和3个试验点开展重复试验，对这些RIL系进行农艺性状评估与SPC表型鉴定。
通过复合区间作图法，我们在PR-30群体中鉴定到3个与SPC相关的QTL，在PR-31群体中鉴定到5个相关QTL，其LOD值范围为3.0至11.0。与此前已报道的SPC相关QTL相比，本研究发现的多数QTL为两个群体所特有。其中QTL SPC-Ps-5.1与早前报道的SPC相关QTL PC-QTL-3存在重叠区域。
三个QTL分别为SPC-Ps-4.2、SPC-Ps-5.1与SPC-Ps-7.2，其LOD分值分别为7.2、7.9与11.3，可分别解释14.5%、11.6%与11.3%的表型变异，可用于豌豆SPC提升的标记辅助育种。
本研究还鉴定到8个与籽粒产量相关的QTL，LOD分值范围为3.1至8.2。其中两组QTL分别为SPC-Ps-2.1与GY-Ps-2.1，以及SPC-Ps-5.1与GY-Ps-5.3，共享QTL/峰值区域。根据QTL区域的亲本来源，每组QTL仅对SPC或籽粒产量其中之一产生正向效应，这证实了在针对SPC开展育种时，需同时考虑其对籽粒产量的影响。