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Utilization of Citrullus germplasm with resistance to Fusarium wilt (Fusarium oxysporum f. sp. niveum) for watermelon rootstocks

Huh, Y.C., Om, Y.H., Lee, J.M.
Acta horticulturae 2002 no.588 pp. 127-132
Citrullus, Fusarium oxysporum, Fusarium wilt, Lagenaria siceraria, crossing, cultivars, disease resistance, fruits, germplasm, greenhouses, hybrids, pumpkins, races, rootstocks, salt tolerance, seedlings, temperature, watermelons, wilting
Citrullus germplasm was tested against Fusarium wilt in several races to breed resistant rootstocks. Physiological characteristics such as low temperature tolerance and salt tolerance, were also compared for utilization as rootstocks. Two accessions, NH 27 and NH 29, with resistance to three races of F. oxysporum f. sp. niveum have been selected. Crosses were made between these lines and other existing watermelon cultivars moderately resistant against Fusarium wilt. When grown under the low temperature conditions, young watermelon seedlings grafted onto NH27xNH29 and NH27x'Calhoun Gray' rootstocks showed comparable growth with those grafted onto conventional rootstocks, 'Shintozwa' pumpkin and 'FR Dantos' bottle gourd. Watermelon seedlings grafted onto the hybrid, NH27x 'Calhoun Gray', exhibited high salt tolerance comparable to the plants grafted onto 'FR Dantos'. Yield and quality of fruits harvested from the watermelon plants grafted onto NH27xNH29 and NH27x'Calhoun Gray' rootstocks were comparable to, or better than, those grown with conventional rootstocks. Thus, Citrullus germplasm is a valuable source in breeding of watermelon rootstocks with Fusarium wilt resistance, as well as cold and salt tolerance. Our rootstock breeding programs should address the need to develop new hybrid varieties by combining the desirable characteristics such as disease resistance, cold and salt tolerance which can make watermelon production suitable under greenhouse conditions.