High temperature effect on the male gametophyte and the photosynthetic activity of two Capsicum annuum L. cultivars

Yanina Arnaoudova, Elena Topalova and Velichka Todorova
Agricultural Academy, “Maritsa” Vegetable Crops Research Institute, 4003 Plovdiv, Bulgaria

Abstract

Arnaoudova, Y., Topalova, E. &Todorova, V. (2020). High temperature effect on the male gametophyte and the photosynthetic activity of two Capsicum annuum L. cultivars. Bulg. J. Agric. Sci., 26 (2), 409–415

Induced mutagenesis is imposed as one of the most powerful methods for creating a starting material in the selection. This also requires extensive research into mutant forms and their hybrid varieties. A prospective trend in selection is the creation of F1 hybrids with high tolerance to abiotic stress. The high temperature (HT) is already a significant factor of the environment when growing different cultural plants and the pollen vitality and pollen fertility occur to be one of the most high temperature stress sensitive indicators.  The effect of high temperature stress on two Capsicum annuum L. cultivars: Cv. Zlaten Medal 7 and cv. Yasen F1, which was created on the basis of male sterility obtained by irradiating dry seeds with a range of Co60 frames, has been investigated.
In the bud formation-blossoming period the plants were exposed to high temperature treatment in two regimes – 40°С/2 h and 45°С/1 h. More sensitive to high temperatures was the male gametophyte of mutant cv. Yasen F1 in comparison to cv. Zlaten medal 7 in which decisive role over the vitality occurred to be the treatment duration. According to the chlorophyll fluorescence analyses, the two HT regimes result in a change in the chlorophyll fluorescence parameters. The influence of the higher HT value with shorter impact duration is more pronounced. The mutant nature of Yasen F1 may be the basis for its higher sensitivity to high temperatures.

Keywords: heat stress; pollen germination; pollen tube length; chlorophyll fluorescence; Capsicum annuum L.

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