Cauliflower is a cool-season crop, and is usually grown in the cool months from October to April in Taiwan. In recent years, Taiwan’s seed sector has developed a number of heat tolerant varieties, and the F1 hybrid seeds of these varieties have been exported to and adapted in China and India. The estimated annual production value reaches US$17 million. However, poor hybridity or contamination of a seed lot with the wrong variety inevitably can occur at different stages of the production process. Starting with the wrong seed causes problems for growers. Hence, the purity testing to determine the percentage of seeds belonging to the heat tolerant varieties/hybrids under certification is of critical importance not only to growers but also seed producers. The value of the seed lot with hybrid seed purity above 95% would be 1.5-3.0 fold of the seed lot with 90%. Nevertheless, the conventional method of growing out the seeds and comparing the morphological characteristics of hybrids to assess their purity is time consuming and labor intensive. Moreover, expression of morphological characteristics is liable to be influenced by environment. Thus it is imperative to develop reliable and efficient molecular techniques that help seed producers to deliver the purest possible seeds to the growers.

    Toward this direction, Taiwan Agricultural Research Institute has developed a Cleaved Amplified Polymorphic Sequences (CAPS) technique that greatly increased the efficiency of hybrid seed purity testing of heat tolerant cauliflower varieties. This newly developed CAPS technique can complete the purity test within two weeks. Compared with the conventional grow-out test that takes eight weeks, it not only saves time but also improves the efficiency with up to 96% accuracy.

    Compared to random amplification of polymorphic DNA (RAPD) or simple sequence repeats (SSR), CAPS is a low-cost and robust PCR-based assay that reliably distinguishes between SNP (single nucleotide polymorphism) alleles with high reproducibility, and holds great promise for genotyping. Experimental results reveal that three primer pairs for CAPS are adequate to carry out purity tests for more than 15 hybrids. The technology has been transferred to two seed companies in Taiwan, and is certain to increase the quality, value and international competitiveness of Taiwan’s vegetable seeds.