Comparison of Traditional Grow-Out Test and DNA-Based PCR Assay to Estimate F1 Hybrid Purity in Cauliflower

Abstract

Cauliflower ( Brassica oleracea ) is a cool-season crop belonging to the Brassicaceae family. Use of morphological differences between true-to-types and off-types in grow-out test (GOT) is the basic method for hybrid purity analysis. Traditional GOT is costly, tedious, time consuming and environment sensitive. To increase the speed and accuracy of genetic purity testing of hybrids, recent advances in DNA markers have shown promise. In the present study, the purity of cauliflower hybrid (NBH Tania-815) was assessed by traditional GOT and advanced molecular marker systems. The experiment was carried out by mixing 95% F1 hybrids with 5% female parents, individually in the sample sets of 400, 300, 200, 100, 80 and 40. For each sample size, PCR-based assay and GOT were carried out to check the hybrid purity. In the PCR-based assay, 220 pairs of SSR markers were screened, with 32 markers showing parental polymorphism including one codominant marker (BrgMS565). The purity level was determined by the co-dominant marker. A minimum sample size of 100 was standardized to confirm the hybrid purity as it showed the same result with that of higher sample sizes (200, 300 and 400). Hence, it is proposed that molecular marker-based hybrid purity assessment may serve as an effective substitute to traditional GOT.