| Upland rice which was the huge precious germplasm resources in drought resistance breeding of rice, had many properties, such as drought resistance, barren-tolerance, wild adaptability and so on. Developing and utilizing upland rice were the efficient solution to reduce drought disserve and solve the food crisis in some degree. And it was also an important measure to solve the water crisis. In this paper, 35 upland rice germplasm were studied in terms of main agronomic traits, quality characters and drought resistance indices. And their genetic parameters, including broad sense heritability, simple correlation, genetic correlation, expected genetic advance, correlated genetic advance, path coefficient and factor load, were analyzed by using variance, covariance and multivariate analysis. The results were as follows:(1) The order of broad sense heritability of 13 agronomic traits was like this: effective tiller stem length > plant height > length of 1st & 2nd rachis > neck length of spike > panicle length > growth duration > flag leaf width > effective panicles per plant > flag length > filled grains per plant > seed set ratio > yield per plant > 1000 grain weight. The broad sense heritability of yield per plant, yield per plant and seed set ratio were low.(2) The order of genetic variation coefficient of 13 agronomic traits was as follows: neck length of spike > filled grains per plant > length of 1st & 2nd rachis > yield per plant > effective panicles per plant > effective tiller stem length > flag leaf width > seed set ratio > plant height > flag length > 1000 grain weight > panicle length > growth duration. Among them, yield per plant had abundant heredity potential, so its selection potential was high.(3) As selection rates were 5% and 1%, the order of expected relative genetic schedule of these 13 agronomic traits was as follows: neck length of spike > length of 1st & 2nd rachis > filled grains per plant > effective panicles per plant > yield per plant > effective tiller stem length > plant height > flag leaf width > panicle length > flag length > seed set ratio > 1000 grain weight > growth duration. Among them, the genetic variation coefficient of yield per plant was up to 29.51%, so it had high heredity potential, swift genetic advance and good selection effect. In this paper, 35 upland rice germplasm all had abundant genetic variation and heredity potential of agronomic traits, and could provide effective heredity bases for further genetic research and breeding.(4) The simple correlation and genetic correlation were found extremely positive correlations between yield per plant and traits like 1000 grain weight, filled grains per plant and seed set ratio (Their simple correlation coefficient were 0.5717**, 0.7584**, 0.7708**and genetic correlation coefficient were 0.7926**, 0.9759**, 0.9835**, respectively ). And when the 1000 grain weight, filled grains per plant and seed set ratio were selected, the relative correlation genetic advance of yield per plant was also high (when k=2.06, the relative correlation genetic advance were 24.6034%, 37.1987%, 33.0304%, respectively), therefore, indirect selection to these 3 traits could increase yield per plant significantly.(5) The result of path analysis on agronomic traits showed that direct effects of 1000 grain weight(x1), filled grains per plant(x2) and seed set ratio(x3) on yield per plant(y) were high, and the optimum regression equation between these 3 traits and yield per plant was as follows: y= -6.6198+0.1852x1+0.0081x2+0.1198x3(SLE=0.10,SLS=0.10). Thus, the effects of selection would be efficient, if the selection was based on the genetic behave of agronomic traits, correlation of traits, effect of traits on yield per plant and optimum regression equation of yield per plant.(6) The result of simple correlation of quality characters indicated that the protein content was extremely significant negative correlated with transparency grade(r=-0.4621**), significant negative correlated with flag length(r=-0.3508*) and growth duration(r=-0.3583*), and significant positive correlated with brown rice rate (r=0.3539*). The amlyose content was extremely significant negative correlated with flag leaf width(r=-0.4679**) and length of 1st & 2nd rachis(r=-0.4427**), positive correlated with chalk rice rate(r=0.3361) and chalk area(r=0.3190), and their positive correlation coefficient were high, but not significant. So, it showed that selecting the traits with obvious correlation could increase the protein and amlyose content in some degree.(7) Grain shape, brown rice rate, chalkiness, gel consistence, protein content, amlyose content were the 6 principal factors of rice quality, and the cumulative variance contribution of them reached 88.0466%. These 6 traits generalized the main information of the12 rice quality basically, so they should be taken into account together in breeding of upland rice quality so as to improve the efficiency and effects of selection. Moreover, they could restrict one another, thus people must pay attention to the cooperation between traits in breeding.(8) The results of drought resistance experiment for 35 upland rice germplasm showed that, 4 indices including leaf water content after excision, wound percentage of cytoplasmic membrane, variation coefficient of tiller stem length and percent germination in -0.86 Mpa PEG solution, were found efficient in examining the drought resistance of upland rice . Path analysis of drought resistance indicated that the order of direct effect of these drought resistance indices on selection of total rank of drought resistance was as follows: percent germination in -0.86 Mpa PEG solution > variation coefficient of tiller stem length > leaf water content after excision > wound percentage of cytoplasmic membrane. And the order of direct effect of the drought resistance indices on selection of yield per plant was as follows: percent germination in -0.86 Mpa PEG solution > variation coefficient of tiller stem length > wound percentage of cytoplasmic membrane > leaf water content after excision. Besides, the total rank of drought resistance was significant positive correlated with yield per plant.(9) 35 upland rice germplasm were divided into 3 groups, based on total rank of drought resistance and dendrogram of drought resistance. Among them, 18 germplasm were the kind with strong drought resistance (drought resistance ability≥3), 12 germplasm with medium drought resistance (drought resistance ability of most of 12 germplasm between 2 and 3), 5 germplasm with weak drought resistance (drought resistance ability <2).Therefore, studying on genetic parameters of main agronomic traits, quality characters of upland rice and drought resistance could provide some theoretical bases for selecting the better quality cross with high yield, high quality and excellent drought resistance and provide some valuable genetic parameters of quality for upland rice breeding. |
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