The use of seedling root and shoot traits to predict the saleable yield of elite red papaya genotypes

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ABSTRACT Determining the saleable fruit yield of red hermaphrodite papaya (Carica papaya L.) relies on waiting until tree maturity. Recombinant inbred lines (RIL) seedlings (F6-F7 RIL) were assessed for fresh root length, fresh shoot weight, fresh shoot width, dry root weight and dry shoot weight during three growth stages after sowing (0-30 days after sowing; DAS, 31–60 DAS and 61–90 DAS). During the 31–60 DAS period, significant intra-genotypic variation was observed for each trait across the RIL assessed. A strong genotypic correlation at growth stage II was predicted among the traits (P < 0.05; rg > 0.60), with a moderate to high broad-sense heritability (H2 b.s; > 0.30) and with genetic advances of up to 10% in the RIL compared to the parental genotypes. Growth stage II was most reliable for predicting saleable fruit yield (R 2 = 0.73) with levels of influence of traits measured across the RIL in the following order: fresh root length (40% to 70%) > dry root weight (20% to 50%) > dry shoot weight (10% to 48%) > fresh shoot width (13% to 38%) > fresh shoot weight (1% to 42%). Hence, these F7 genotypes will be used to develop new F1 hybrids with significant increases in saleable fruit yield.