GRAFTING SWEET PEPPERS FOR PRODUCTION IN THE HOT-WET SEASON
SWEET PEPPERS are difficult to grow during the hot-wet season. High rainfall, flooding, waterlogged soils, diseases, and high temperatures can significantly reduce yields.
Grafting sweetpepper scions onto selected rootstocks of sweet pepper and chili (hot) pepper can minimize problems caused by flooding and soil-borne diseases, including bacterial wilt and Phytophthora blight.
Sometimes, the use of grafted pepper plants can make the difference between harvesting a good crop and harvesting no crop at all (Fig.1).
GRAFTING OPTIONS Producing grafted sweet peppers is more expensive than non-grafted pepper production.These tolerate waterlogging and survive for days under water.Use grafting only when there is a risk of flooding or soilborne diseases such as bacterial wilt and Phytophthora blight.
Chili pepper rootstocks Use chili pepper rootstocks when flooding or waterlogged soils are expected. Chili roots can tolerate waterlogging and survive for days under water.
Most chili lines will graft successfully with sweet pepper lines. The key is to identify chili rootstocks that will maintain the high yields and fruit quality of the scion variety. The lines should be
resistant to bacterial wilt (caused by Ralstonia solanacearum) and other soil-borne diseases.
AVRDC – The World Vegetable Center in Taiwan recommends chili accessions PB02377502,0242-62,and LeeB. They are resistant to damage caused by flooding, bacterial wilt, and Phytophthora blight (caused by Phytophthora capsici). Field observations indicate these lines show tolerance to both diseases.
Sweet pepper rootstocks Most sweet pepper varieties are susceptible to damage by soil-borne diseases and flooding. Therefore, it is not advisable to use sweet pepper rootstocks until resistant or tolerant lines are identified. So far, no resistant lines have been developed at AVRDC or other research institutions. Breeding for disease resistance and flood tolerance is in progress.
Figure 1. Grafted sweet pepper plants (left bed) are growing vigorously while non-grafted plants (right bed) are dead.