G.K. Kisileva’s scientific contributions

Fruit growing and breeding is an important business and cultural activity to provide healthy food for the population and utilize, maintain and develop landscapes. Global and regional climate change is creating a current need for physiological and biochemical studies on apple resistance to abiotic stress factors. Apple trees’ high potential adaptive capability depending on the landscape was revealed in domestically bred apple tree varieties under conditions of extreme environmental influences, which makes it possible to use them in the breeding process as a source of traits promoting winter hardiness and drought resistance. It was established that the biochemical adaptation of the apple tree varieties to low-temperature stress is achieved by synthesizing the increased number of osmoprotectors (saccharose, proline), anthocyanins, chalcones, phenolcarbonic and abscisic acids, and by the increase in the calcium cation content and peroxidase activity, too. Resistance to high-temperature stress and drought is characterized by a high content of bound water, proline, saccharose and phenolcarbonic acids, a stabler content of total chlorophylls in the period of exposure to stress; the accumulation of carotenoids, and the formation of a xeromorphic leaf plate structure. The apple tree varieties were identified which featured high resistance to the damaging factors of the winter period, which were promising for use in plant breeding and production in the Krasnodar Territory. The results obtained will make a significant contribution to the study and optimization of agricultural landscapes.

In the North-Caucasus region of the Russian Federation, where the draught is a frequent phenomenon, the apple-tree is among the most important horticultural crops. The physiological-biochemical research is necessary for impartial assessment of the apple-tree varieties’ adaptation tolerance to the summer period stressors, summer draught in particular. The objective of the present paper – based on the physiological-biochemical and leaf anatomic parameters – is to study the peculiarities of water status, apple-tree photosynthetic activity in the terms of summer period, single out the most drought-resistant varieties to cultivate in conditions of the North-Caucasus region of the Russian Federation. The research was undertaken in 2011-2013 on the basis of Pilot production farm “Centralnoye” in Krasnodar city on 9 apple-tree varieties, varying in ecological-geographic origin (USA, Poland, Russia) and ploidy (di-and triploid). It was shown that water content of the leaf tissues, an indicator of bound and free water form relation, was a function of the variety and meteorological condition peculiarities. Prikubanskoye, Fortuna, Soyuz, Rodnichok varieties showed the decrease in water content by 1-4 percent on average and the highest indicators of bound and free water form relation. The linear parameters of leaf depended on variety pertainance and hydrothermic conditions of year within a vegetation period. In Prikubanskoye, Fortuna, Soyuz, Rodnichok varieties the direct correlation was found out between the area of leaf blade and available water supply (r = + 0.98), negative one – between the area and air temperature (r =-0.99). The water and temperature regimes have an impact on the crop productivity, as well as on setting the fruit buds, that was confirmed by the coefficient of pair correlation between chlorophylls totality and crop productivity (r = +0.87), water content of tissues and setting the fruit buds (r = +0.97). The chlorophylls totality content of Prikubanskoye, Fortuna, Soyuz, Rodnichok varieties was more stable within the summer period, and indicator of the chlorophylls totality and carotinoids relation was the highest one. The positive correlation was revealed between the carotinoids content and air temperature (r = +0.91). The anatomomorphological structure of leaf has the variety peculiarities, it depended on temperature and available water supply. In the year 2012 the varieties displayed to different extent the xeromorphous signs of leaf blade, responsible for the draught resistance, the largest values of palisade index were noted in Prikubanskoye, Fortuna, Soyuz, Rodnichok (1.47-1.49) varieties. The obtained results were in agreement with the field data, obtained in the non-irrigated gardens. The varieties displayed the different peculiarities of suffering the stress factors of summer period – the high temperatures and draught. In Idared, Erli Mac, Dayton, Ligol varieties the steadiness of passive suffering the draught – the decrease in water content, high content of dry matter, lesser leaf area. In the rest of varieties – the retention of high water content, stability of the growth processes, high content of pigments. The home-selected apple-tree varieties, such as Prikubanskoye, Fortuna, Soyuz, Rodnichok, feature the higher ecological plasticity and reserve of potential adaptation abilities, as compared with the introduced varieties of foreign selection. The revealed adaptation peculiarities permit to use them in selection process as the sources of drought resistance. The applied methods provide the impartial assessment of the apple-tree draught resistance and may be used in selection process.