Evaluation of heterosis through reciprocal crosses of inbred cucumber lines (Cucumis sativus L.)

The purpose of the study. The aim of the study was to determine the effect of heterosis in short-fruited parthenocarpic F1 cucumber hybrids by the main economically valuable characteristics, when grown using low-volume technology in industrial greenhouses of the Moscow region. Materials and methods . The object of the study is short-fruited parthenocarpic reciprocal hybrids of cucumber Druzhny (F 1 I 7 3514 x I 7 4011), F 1 I 7 4011 x I 7 3514 and their parent inbred lines I 7 3514 and I 7 4011 of selection by N.N. Timofeev Breeding Station LLC. F 1 SV4097CV of foreign selection of Semenis company (Netherlands) was used as a control. The study was conducted in 2020-2021 in industrial greenhouses of the "V. I. Edelstein Vegetable Experimental Station" of the K.A. Timiryazev Russian State Agrarian University-Moscow Agricultural Academy in Moscow on low-volume hydroponics in peat bags. Parental lines and hybrid combinations were evaluated by earliness, early yield, yield, number of fruits per plant, average fruit weight and marketability. Results . According to the results of the study, F 1 Druzhny (F 1 I 7 3514 x I 7 4011) and the reverse hybrid I 7 3514 x I 7 4011 demonstrated high positive effects of heterosis in yield (MPH=19.4...22%; HPH=13.4...15.9%; CH=9.6...12%) and the number of fruits per plant (MPH=22.5...26.4%; HPH=12.5...15.8%; CH=11.7...15%). Negative indicators of the heterosis effect were noted for earliness from germination to flowering (MPH=-3.4...-1.1%; HPH=-6.5...-4.4%; CH=-4.4...-2.2%) and average fruit weight (MPH=-2.2...-1.3%; HPH=-5.3...-4.3%; CH=-3.4...-2.4%). The value of the degree of dominance indicates the presence of positive overdominance in the inheritance of such traits as yield (hp=2.7...3.2), the number of fruits from the plant (hp=1.5...1.9) and marketability (hp=1.6...2.3). Negative overdomination was observed in earliness from germination to flowering (hp= -2...-1.3) and average fruit weight (hp=-1.7...-1.2). According to the signs of earliness from germination to fruiting (hp =0) and early yield (hp=-0.1...0.5), intermediate inheritance was revealed. The Druzhny hybrid significantly exceeded the control hybrid SV4097CV in early yield, yield and number of fruits from the plant, and the reverse hybrid F 1 I 7 4011 x I 7 3514 was at the control level, which indicates the prospects of growing these hybrids in the conditions of spring-summer turnover on low-volume hydroponics.