Microspore culture is a key method for rapid development of genetically uniform lines. In this study, we aimed to identify the critical factors influencing the efficiency of microspore culture in Chinese cabbage (Brassica rapa), which is an important vegetable crop widely cultivated worldwide for its genetic diversity and nutritional value. To this end, we compared the efficiency of microspore embryogenesis across four different Chinese cabbage genotypes. We selected three accessions representing high, medium, and low efficiencies. Flower buds were harvested to examine pollen developmental stages using a light microscope. Unexpectedly, we found that the genotype with the highest efficiency (Wonkyo20044ho) had abnormally shaped microspores and pollen. In contrast, the genotype with the lowest efficiency (Wonkyo20039ho) had fine, normally shaped pollen. An additional experiment was conducted using the Wonkyo20044ho accession. Different bud sizes were harvested from this accession to observe differences in embryogenesis. The results showed that almost all pollen stages of this genotype were suitable for microspore culture. It can be assumed that the genotype is much more critical for microspore culture efficiency than the developmental stage of the pollen. Our results serve as a valuable reference for improved cabbage breeding methods.

Watermelons are grafted to prevent soil-borne diseases such as Fusarium wilt (FW) and increase their resistance to abiotic stress. Root-knot nematodes (RKN) are a contributing factor to economic loss in several cucurbits, including watermelon. Growing resistance varieties is an effective way to reduce the damage caused by soil-borne diseases. Resistance evaluation was performed on 50 watermelon lines to select rootstocks resistant to FW and RKN. Fusarium oxysporum f. sp. niveum race 2 was inoculated into 10-day-old seedlings using a root dipping method, and resistance was evaluated for four weeks. The 37-day-old watermelon seedlings were inoculated with Meloidogyne incognita and evaluated 60 days later. Three lines (IT199860, PI296341-6, and PI532811) were resistant to FW race 2, while one line (PI494527) was moderately resistant. Three lines (PI296341-5, PI457916-2, and PI457916-5) were RKN resistant. The PI296341-6 line was selected for its resistance to FW and moderate resistance to RKN. These findings imply that the identified resistant lines can be used in rootstock breeding programs against FW and/or RKN.