ARS | Publication request: MICROPROPAGATION FOR RECOVERY OF CUCUMIS HYSTRIX CHAKR

Submitted to: Plant Cell Tissue And Organ Culture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 30, 2002
Publication Date: N/A

Interpretive Summary: Plant germplasm (plants that man uses for food and fiber) is important to mankind since unique plants are receivers for disease resistance, water and heat tolerance, and yield and quality genes (points on chromosomes which control economically important traits). Cucumber is a crop species which possesses relatively little variation in the genes for important economic traits. Plant geneticists and breeders work to incorporate genes from wild exotic species to introduce useful genes into cucumber through controlled pollination. We have identified a wild species that can be mated with cucumber to produce plants that can increase the genetic diversity of cucumber and therefore increase the potential for the incorporation of useful genes from the wild species into cucumber. However, it is difficult to reproduce the wild species under North American growing conditions. Therefore, we conducted experiments that resulted in the establishment of growing wild species and use them freely to incorporate useful genes into cucumber under any growing condition. This procedure increases the effectiveness of plant breeders to improve commercial cucumber.

Technical Abstract: A micropropagation protocol that allows for the efficient cloning of C. hystrix was developed using 1mm shoot-tip explants prepared from plants grown in the greenhouse. Establishment of Stage I cultures was greatest (83%) when shoot tips were cultured in modified MS medium containing (per liter) 30g sucrose, 0.1 g myo- inositol, and 5 g Agargel plus 1.7 uMIBA, 0.5 uM kinetin and 0.3 uM GA3 (IKG). Benzyladenine (5 uM) proved best for Stage II shoot proliferation. Over 35 shoots were obtained per vessel (five shoots per vessel) when explants were cultured in medium containing BA. Less than 10 shoots were obtained per vessel when kinetin (0.5- 5 uM) and IKG were used. Stage II cultures established from 1 cm shoot tips obtained from Stage I shorts produced more shoots (1.3- fold) than single node explants. Rooting and plantlet acclimatization were best when shoots greater than 1.5 cm were incubated in MS medium containing 0.5 uM NAA. Higher NAA concentrations stimulated rooting but inhibited shoot elongation and reduced the ability of plantlets to survive acclimatization to ambient conditions. Plantlet height influence acclimatization. Over 72% of plantlets survived acclimatization if they were at least 4.6 cm when transferred to soilless growing medium.