Assessment of cold resistance in <i>Momordica charantia</i> l. accessions according to pollen germination at low temperatures <i>in vitro</i>

Abstract

Background. Bitter melon (Momordica charantia L.) is a vegetable and medicinal crop new for Russia. Its high heat demand is the main factor limiting the possibilities of its cultivation in a temperate continental climate. Evaluation and selection of more cold-resistant accessions is required for breeding new cultivars and expanding production. Previously obtained data attest to a possibility of assessing cold hardiness in the mature male gametophyte phase in vitro.Materials and methods. Eight bitter melon accessions, including parent forms, F  hybrids and cv. ‘Gosha’, were grown in the unheated film greenhouse of the Central Siberian Botanical Garden, Novosibirsk (54°49’ N, 83°06’ E) for evaluation and selection for cold resistance. The ratio of pollen germination in vitro on a 15% polyethylene glycol solution with a molecular weight of 6000 (PEG 6000) with the addition of boric acid (0.006%) at a temperature of 10°C for 24 h to the same indicator at 25°C / 3 h (in %) was used as a criterion of cold resistance.Results. The cultivar ‘Gosha’, the accession Okinawa green from Japan, and the F1 hybrid (Feng Guang × Okinawa green) had the highest cold resistance, with the values of 59.7; 53.8 and 48.2%, respectively. The inheritance of cold resistance in F , assessed by the pollen germination index, depending on the crossing combination, changed from intermediate in two hybrids [F1 Feng Guang × Gosha) and F1 Feng Guang × Okinawa green)] to overdominant (positive heterosis) in the hybrid F1 (Feng Guang × Okinawa white).