Production of new early ripening hybrids of large fruited pumpkin (Cucurbita maxima) based on functional male sterility

Abstract

Breeders of the All-Russia Research Institute of Irrigated Vegetable and Melon Growing created new breeding valuable maternal lines CL fms (cut-leaved, choriphyllous) and EL fms (entire-leaved, integrifolious) with the functional male sterility and high general combining ability suitable for the production of early ripening F₁ hybrids of large fruited pumpkin. The conducted analysis of pollen of the forced open anthers of flowers with the functional male sterility demonstrated its high fertility (90.2%) allowing the use of this pollen for artificial pollination. It was found that the functional male sterility of large fruited pumpkin is inherited recessively and controlled by the one gene. Maternal lines CL fms and EL fms demonstrated a high level of general combining ability for the “ripeness” trait. F₁ hybrids obtained based on these lines were superior to the standard mid-early ripening pumpkin variety Kroshka at 10–18 days; isolated hybrid combinations were at the level of standard variety in terms of yield and solids content. Maternal lines CL fms and EL fms allow the production of the hybrid offspring with brightly colored fruits in contrast to the maternal line LF fms (large fruited) that provided the hybrids with fruits that had different shades of gray color of the cortex. The majority of hybrid combinations allow obtaining fruits of portion size with an average weight of 1–3 kg and high productivity. F1 hybrid combination EL fms × Konfetka-ultra early ripening with colored fruits of portion size and high biochemical indexes was distinguished based on the complex of agronomic characters.