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Mutalova M.K., PhD senior researcher Ismailova D.M. basic doctoral student UzRFA Institute of Genetics and Experimental Biology of Plants
Uzbekistan, Tashkent region
VIABILITY ANALYSIS OF DUST GRAINS OF COTTON VARIETIES AND HYBRIDS IRRADIATED IN GAMMA RAY SOURCE BASED ON COBALT-6O RADIOISOTOPE (6O-SO) (M i)
Abstract. The article presents the results of the analysis (M1) of pollen grains of varieties and hybrids of cotton irradiated in a source of gamma rays based on cobalt-60 radioisotope (60CO).
Key words: cotton, variety, hybrid, pollen grains, mutation, flower.
Introduction. Mutagenesis is the engine of evolution. All our normal genes are yesterday's "mutants" that have conditionally proven their usefulness. Due to mutations, bacteria became the first microorganisms with a cell nucleus, and they became multicellular, giving rise to all the diversity of life forms.
A mutation is a change that affects a DNA, gene, or chromosome. This can be caused by various external and internal factors. Mutations often occur before the process of mitosis, when the DNA molecule is replicated in the cell nucleus. For example, UV radiation causes errors in replication. Mutational variation creates new genes or changes existing ones, thereby enriching the population's gene pool. Mutations of each individual gene are rare in nature [1].
In order to increase the productivity and scope of economically valuable mutations, scientific research is being conducted to find factors that change the mutagenic effect, to determine the role of genotype in experimental mutation, and to determine the environmental conditions in the manifestation of the genetic potential of induced mutants. The expediency of revealing hybrids obtained as a result of crossing cultivated and wild forms that are close to each other within the species and genetically distant from each other is also important for the issue of using the experimental mutagenesis method in selection in order to improve individual, lacking economically important characters in industrial varieties. 'attention [2], [3]
Literature review. It turns out that the closer the varieties are to each other in terms of origin and genotype, the more similar the rate and character of mutation will be. This confirms that NI Vavilov's law of homologous series in genetic variation is correct. The temperature before and after irradiation, the conditions of the light regime during the irradiation period have a great influence on its result. Irradiation at low temperature increases the rate of chromosomal changes, and high temperature reduces the number of mutations. During radiation,
high temperature has a regenerative effect on chromosomes. A short bright day has the same effect. If the seed has been irradiated, this year there will be a slight slowdown in the development and production of cotton. The development of all plants, the external appearance of the bushes, the shape of the leaves, the buds, and the lack of reproduction will change dramatically from the norm. There are very large and small plants. Most of them will be unviable. Most of the changes under investigation are called radiomorphosis, which revert to the original in later generations. Radiomorphoses are not adaptive variations, so they are less viable.
Research methodology. The analysis of the viability of dust particles was carried out in laboratory conditions. To determine fertility, pollen was collected from ten flowers of each plant. The study of the viability of dust grains was carried out using the methodology of Z. Pausheva [6]. The most effective way to determine the viability of dust grains is in vivo [7]. Chemical dyes that give color can be used to determine whether it is fertile or sterile. The acetocarmine method was used to determine the viability of dust grains. For this, mature flower pollen was placed in carnoia fixative. Pollen was placed in Carnois fixative for half an hour to several hours. The material was washed and preserved in an 80% solution of ethyl alcohol. After that, the dust grains settle on the glass of the product, a drop of acetocarmine is added and covered with a coverslip. Heated in alcohol and seen under a microscope. From dust grains prepared preparations were examined under a microscope at different magnifications (10x, 40x, 100x) under a binocular microscope. In addition, it is possible to determine the fertility directly with acetocarmine or iodine without putting the pollen grains collected from the plant in a fixative. Granular cytoplasm and spermatozoa in viable pollen grains are stained carmine red. Sterile pollen grains are almost not stained with acetocarmine, or the color is unevenly distributed in the cytoplasm of pollen grains. The number of stained and unstained dust particles was counted for analysis. The number of stained and unstained dust grains was statistically analyzed, and the viability of dust grains (%) was interpreted as a percentage.
Analysis and results. Studying and researching the viability of plant pollen grains is important in solving many problems of practical selection. Pollen grains are formed in the anthers of flowers and develop from a microspore in a microsporangium. Environmental pollution has a negative effect on the productivity of plants. The main amount of pollutants accumulates in the vegetative organs, in turn, problems arise in the reproductive organs of the plant, and the viability and quality of dust particles decrease under the influence of aerotechnological pollutants.
Of two combinations, varieties and lines of cotton crossbred in our laboratory was irradiated at the Institute of Nuclear Physics under the Academy of Sciences of the Republic of Uzbekistan.
Different amounts of radiation provide different benefits. Accelerating, critical or mutagenic and lethal amounts are distinguished. Cobalt-60 radioisotope
(60 with the absorption power of 0.05 Gr/s after irradiation of hybrid samples of cotton with gamma rays.
Irradiated in a gamma ray source (see Fig. 1).
C6O-C0) F O ivim K^aop ycMM^MK
Figure 1. Irradiation of hybrid samples of cotton with gamma rays, irradiation in a source of gamma rays based on Cobalt-60 radioisotope (60^o) with an absorption intensity of 0.05 Gr/s.
1) Stimulator-1 (weak)
2) Incentive -2 (medium)
3) At the mutation level (strong) irradiated and stored for a period of rest.
The purpose of irradiating hybrids is to increase the number of crossing
overs that destroy the linkage groups in them, and thus isolate and multiply unique combinations.
It is known that the effect of gamma rays on cotton seeds causes changes in a number of morphological characters. Changes in characters such as leaf color, type of branching, number of branches, stem growth, etc. are mainly conservative-hereditary. the rea^n for sharp morphological changes in cotton is the genetic changes that occur under the influence of gamma rays under the influence of external conditions. In addition, a number of paratypic (or modification) changes of quantitative characters under the influence of environmental conditions are determined. For example, early maturity, fiber length, yield and quality of cotton are subject to ^me degree of paratypic variation depending on the agronomic practices used and ^il-climatic conditions. [4], [5].
In the course of our research, the effect of gamma rays based on cobalt-60 radioiСоtope (60-^) on the generative organ of plants, i.e. pollen grains, was studied. (See Figure 2).
m
• W
Figure 2. M i of Ghoza General view of pollen grains of L-21 x Elastic hybrid.
According to the results of the research, Indicators of viability of cotton grains of varieties and hybrids irradiated in a gamma ray Соurce based on cobalt -60 radioiСоtope (60-^) (see Table 1) Hairless I amount 80.2%, II amount 79.9%, III amount 71.4%, Future-2 I amount 80%,
Amount II 88.0%, Amount III 72.9%, Future Amount I 82.5%, Amount II
90%,
Indicators of viability of dust grains of varieties and hybrids of cotton irradiated in a Cource of gamma rays based on cobalt-60 radioiCotope (60-
Co) (M 1)
Table 1
Varieties and hybrids How Analyzed Fertile Sterile Powdered
much? powder powder powder grains
particles grains granules the
total viability of
number of (%)
Hairless I 8118 6512 1606 80.2%
II 3014 2410 604 79. 9 %
III 3148 2250 898 71.4%
Future-2 I 4556 3002 1554 80%
II 6787 5975 812 88.0%
III 1850 1350 500 72.9%
The future I 5021 4145 876 82.5%
II 3046 2743 303 90%
III 2950 2240 710 75.9%
Future x Future-2 I - - - -
II 8785 8002 783 91.0%
III 3246 2712 534 83.5%
Future L-21 I 3785 2850 935 75.2%
II 10177 8000 2177 78.6%
III 5947 5151 796 86.6%
L-1305 I 2933 2150 783 75.8%
II 5023 3950 1073 78.6%
III 8885 7251 1634 81.6 %
LM x Future I 7847 5896 1951 75. 1 %
II 1985 1518 467 76.4%
III 2980 1988 992 66.7%
Elastic x Future I 2018 1803 215 89.3%
II 3460 2951 509 85.2%
III 4054 3247 807 80.0%
L-21 x Elastic I - - - -
II 3450 2880 570 83.4%
III 9782 7813 1710 65.8 %
The low index in the III volume was 75.9%, the high result in the Future x Future-2 I volume was 91.0%, and in the III midor it was 83.5%. In the first generation hybrids of cotton irradiated in the Cource of gamma rays based on cobalt-60 radioiCotope (60-Co), Kalajak x L-21 I amount 75.2%, II amount 78.6%, III amount 86.6%, LM x Kalajak I amount 75.1, As a result of the analysis, it was determined that the viability of dust grains was 78.6% in the amount of II, 81.6% in the amount of III, 83.4% in the amount of L-21 x Elastic II, and 65.8% in the amount of III.
Summary: It should be noted that varieties and hybrids of cotton irradiated in a Cource of gamma rays based on cobalt-60 radioiCotope (60-Co) The analysis of vitality (M 1) revealed different effects on plants in different amounts of radiation and it was found that it was 65.8%-91.0%
Cytomorphological analysis of pollen is important for genetic and selection work, because information about the stage of development,
the diameter of the dust grains, the degree of coloring allow us to more accurately assess the productivity of the sample, the success of pollination is determined, which directly affects the yield.
References:
1. Banks G. R., Mutagenesis: a review of Come molecular aspects, «Science Progress», 1971, v. 59, № 236.
2. abtohomob В.А. Действие гамма-лучей 60Co при различшм CBeTOBoM режиме на мoрфoлoгическую roMeH4mocrb растений хлoпчатника. В сб.: Bonpocbi генетики, селекции и семенoвoдства хлoпчатника и люцерны, вып.13, Ташкент, 1976,с.41-44
3. Азимoва А.Г. Наследoвание индуцирoванных радиацией мутаций хлoпчатника и их испoльзoвание в селекции. Автореф. дис. канд.с. -х.
4. Cabbarov 9.R., Msmmsdov F.M. Quraqliga davamli pambiq Cortlarmm suvarma rejimlsrinin mshsuldarliga tssiri. Azsrbaycan Aqrar Elmi. 2014; 2: 7577.
5. Jabbarov A.R., Mammadov F.M. Influence of irrigation regimes of drought-resistant cotton varieties on yield. Azerbaijan Agrarian Science. 2014; 2, 75-77. (In Azerb.)
6. Паушева З.П. Практикум no цитагогии растений. - 4"е изд., перераб. и дoп. - М.: Агрoпрoмиздат, 1988. - C.208"2010
