S.M. Baibossynova, PhD in Agricultural Science

(Kazakh Rice Growing Research Institute. Corp LTD)

EFFECTS OF YEARS ENVIRONMENT ON RELATIONSHIP OF MILLING GRAIN QUALITY COMPONENTS OF RICE

In modern work of rice breeding – the main cereal cropper of Kyzylorda region – the percentage of head rice per a crop acre is of primary importance. The percentage of head rice is directly related to the accompanying quality production data (shape of grain, hull content, translucent, cracking, and “white body”).

In these latter days the frequently changing and unstable weather and climate conditions, caused by the Aral environmental crisis, have adverse effect on quality features, which, in their turn, reduce the efficient productivity. In this connection the main requirement imposed to the new of rice variety, along with its productivity, is a combination of high quality and sustainability against adverse environmental factors. Great theoretical and practical incentive to develop efficient selection methods is presented by revelation of correlation principles of selected features. The goal of this research is to study association of rice grain cereal properties and their changeability depending on cultivation year conditions.

The research materials included pattern seeds of 63 varieties and selection lines of Kazakhstan, Krasnodar and Primorsky verges, Rostov region, Russia, Uzbekistan, Ukraine, Spain, France, Italy, Hungary, Romania, Bulgaria, China, Japan, Korea, Nepal, and Afghanistan. In accordance with methodological recommendations of N.I. Vavilov VIR [1], on the laboratory polisher (ЛУР-1М) processing unit was used to analyze main features (indications) of rice grain cereal properties: length (L), width (W), thickness (Т) of caryopsis, ratio of length to width of caryopsis (L/W), hull content (HC), translucent (Тt), cracking (C) of endosperm, number of grains with lengthwise mealy spot by the lower ventral edge of caryopsis (“white body” - WB), percentage of polished rice (PPR), percentage of head rice (PHR). Thereafter among all analyzed features there were calculated the correlative coefficients of phenotypic correlations with the use of SAS Institute [2] applications on a personal computer.

The analyzed material was grown in Y2006 and Y2007. According to the Kyzylorda Hydro-meteorological Center’s data, the monthly mean temperature of August 2007 was 3.5ºC higher than the same in Y2006, and 4.9⁰С higher than the average annual. Hot weather conditions of August facilitated the advance ripening and formation of low quality grains. The September temperature ambience was also adverse. The monthly mean temperature in Y2007 turned to be 1.5⁰С lower than in Y2006.

Our studies have defined that varying environmental conditions may cause changes not only in quality features, but also in relations among them. Association parameters of quality features were ranged into the three groups: 1) correlations steady credible; 2) steady non-credible; and 3) unsteady credible and non-credible (varying by years).

The first, steady credible group, includes correlations of the following features: L-W (-0,42 and -0,34 with patterns grown in years 2007 and 2006 respectively), L-Т (-0,38 and -0,51), L-L/W (0,79 and 0,85), W-T (0,77 and 0,61), W-L/W (-0,81 and -0,77), W-WB (0,70 and 0,62), T-WB (0,67 and 0,60), L/W-WB (-0,48 and -0,50), HC-PPR (-0,91 and -0,84), T-L/W (-0,61 and -0,64), Тt-PPR (0,30 and 0,33).

Cultivation-year-independent non-credible relationship (Group 2) were observed in pairs L-HC (0,27 and 0,19), L-Тt (0,07 and 0,01), L-C (-0,21 and -0,25), L-WB (-0,24 and -0,27), W-HC (-0,19 and -0,11), W-C (0,14 and -0,01), W-Тt (-0,28 and -0,30), W-PPR( 0,20 and -0,12), Т-HC (-0,31 and -0,28), Т-Тt (-0,11 and -0,22), Т-PPR (0,27 and 0,24), Т-C (0,04 and 0,05), L/W-Тt (0,17 and 0,17), L/W-C (-0,19 and -0,19), HC-Тt (-0,22 and -0,18), HC-C (-0,13 and -0,29), HC-WB (-0,04 and -0,06), Тt-WB (-0,25 and -0,22), C-WB (0,02 and -0,10), C-PPR (0,11 and 0,29), WB-PPR (-0,03 and -0,11).

Unsteady parameters of accompanying features are presented in Table 1.

Table 1. Phenotypic Correlations of Accompanying Features Depending on Cultivation Year

Correlating Features	Years
	2006	2007
L-PPR	-0,29	-0,44
L/W-HC	0,19	0,32
L/W-PPR	-0,15	-0,45
Тt-C	-0,05	-0,33
Note: critical values r under 1% level of importance 0.32

Statistically valuable negative correlation has been noted between L and PPR and L/W and PPR in an adverse year against the more optimal conditions of Year 2006. Presence of positive relation L/W-HC in adverse conditions points out the increasing hull content, which may result into decrease percentage of polished rice. Negative relation Тt and C increased in an adverse year. This means that Тt serves as a limiting factor for cracking formation in caryopsis under changing environmental conditions. Selection value of the “translucent” indication is also caused by its non-credible correlation with brown rice shape. This allows it to perform selection of genotypes with highly transparent endosperm and various shape of caryopsis.

The most interesting for selection performing is relationship of accompanying indications with main feature (percentage of head rice - PHR) and their changeability under environmental effect (Table 2).

Relation with the main indication of features W, Т, WB and PPR was insufficient under effect of stress-inducing climate factors of year 2007. Credible negative correlation of PHR with features L, L/W, C was present during the both testing years. Practical experience knows the regular negative influence of these features on the percentage of head rice.

Table 2. Association of PHR with Accompanying Quality Features Depending on Cultivation Year Conditions

Correlating Features	Years
	2007	2006
PHR – L	-0,48	-0,46
- W	0,28	0,36
- Т	0,28	0,33
- L/W	-0,37	-0,48
- HC	-0,20	-0,18
- Тt	0,35	0,19
- C	-0,63	-0,64
- WB	0,25	0,29
- PPR	0,32	0,23
Note: critical values r under 1% level of importance 0.32

Positive correlation of PHR-Т in an adverse cultivation year conditioned by reducing cracking formation in caryopsis proves the increased sustainability and plasticity of more translucent varieties in extreme environmental conditions. That is why translucent of endosperm is not only a highly reliable selection criterion for rice grain production properties improvement, but also is an important factor of abiotical sustainability of varieties during the stage of ripening.

Evaluation of grain quality shall firstly be based on translucent of caryopsis endosperm. Analysis of this feature, as it was shown earlier [3], may be performed on singular caryopses beginning from the very first stages of selection work.

References

1. Instructional Guidelines for Production Evaluation of Rice Pattern Grains; Classifier of Rice Production Properties. – Leningrad – 1984 – 12 p.

2. SAS Institute Inc. SAS/STAT user''s quide, Version 6, Fourth edition, Cary (Nc), -1989. -№1.

3. S.M. Baibossynova. Development of Production Evaluation Methodology on Singular Rice Grains. – Kazakhstan Agricultural Science Magazine – 2007 - №3- pp.6-7.