A DISTANT CITRUS HYBRIDS ASSIMILATORY APPARATUS AS A NONSPECIFIC RESISTANCE MECHANISM ELEMENT

Abstract

The humid subtropics of the Krasnodar Territory are a zone of risky citrus growing, which is associated with lower temperatures in winter. Critical temperatures (from minus 7 to - 12?) lead to damage or death of plants, as well as high summer temperatures that affect productivity. Therefore, the creation of distant hybrids and the selection of the most adaptive genotypes to growing conditions is an important element of the breeding process. The most resistant relative of citrus crops is Poncirus trifoliata (L.) Raf., were carry physiological-biochemical and anatomical-morphological researchesof these hybrid forms and their parents and were dentified the most resistant to hydrothermal factors (19; 019-1; 019-2 and 019-A-1), which are carriers of adaptability signs and represent valuable material for practical selection.The degree of plant adaptability to growing conditions is closely connected with the content of chlorophylls and carotenoids, which are a nonspecific plant defense mechanism against abiotic stressors. During the vegetational season, the total chlorophyll content varied from minimum in February (1.47 mg / g in Citrus sinensis 'Valencia') to maximum in October (4.29 mg / g in interspecific hybrid 019-1 from a combination of crossing Fortunella ? C. trifoliata).From February till October, observed an active synthesis of green pigments in the hybrid form 019-A; accumulation of the amount of chlorophyll marked in the autumn period (October) by forms 019-A-1 and 019-2, a significant decrease in the level of chlorophyll observed in June in forms 19; 019-1 these forms in the accumulation of the green group of pigments are manifested to a greater extent by the combination of the features of Fortunella - C. trifoliata, from these it can be proposed that they are resistant to hydrothermal conditions during the period. Analysis of the dynamics of ? chlorofillov /? carotenoids  allowed to mark forms 019-A and 019-A-1 with high rates of 5.31 - 4.64 mg / g wet weight , which suggests their resistance to high summer temperatures.