To study the relationship between rice leaf color change and grain filling,two indica-japonica hybrids with distinct leaf colors were grown under three N fertilizer dosages(LN,0 kg ha^(−1);MN,150 kg ha^(−1);HN,300 kg ...To study the relationship between rice leaf color change and grain filling,two indica-japonica hybrids with distinct leaf colors were grown under three N fertilizer dosages(LN,0 kg ha^(−1);MN,150 kg ha^(−1);HN,300 kg ha^(−1)).The leaf color change features of flag leaf,2nd leaf and 3rd leaf,as well as grain filling traits of superior and inferior grains were compared.Compared to cultivar CY167(normal green leaves)under the same N level,cultivar CY927(dark green leaves)exhibited delayed leaf color change onset time(T_(0))by 0–3.6 d,reduced mean leaf color change rate(R_(m))by 1.98%–9.45%,and increased leaf color index at maturity(CI_(f))by 3.77%–53.48%.Additionally,CY927 prolonged the grain filling period(D)of inferior grains by 0.6–2.0 d,resulting in a yield increase of 8.13%–25.46%.N supply significantly increased rice yield,primarily by delaying T_(0)and reducing R_(m)of flag leaf,improving initial grain filling potential(R_(0))and maximum grain weight(A),delaying the time to reach the maximum grain filling rate(T_(max)),and prolonging the grain filling activity period(D)of inferior grains.The time interval(T_(L-G))between the T0 of the flag leaf and T_(max)of inferior grains was negatively correlated with yield(−0.780,P<0.01).Suggesting that rice yield can be improved by optimizing N fertilizer management to shorten the T_(L-G).These findings provide valuable knowledge about the relationship between leaf senescence and grain filling,and benefit the understanding of the physiological mechanisms underlying high-yield rice production.展开更多
Taking a published natural population life table of rice leaf roller, Cnaphalocrocis medinalis （Lepidoptera： Pyralidae）, as an example, we estimated the population trend index, I, via re-sampling methods （jackknif...Taking a published natural population life table of rice leaf roller, Cnaphalocrocis medinalis （Lepidoptera： Pyralidae）, as an example, we estimated the population trend index, I, via re-sampling methods （jackknife and bootstrap）, determined its statistical properties and illustrated the application of these methods in determining the control effectiveness of bio- agents and chemical insecticides. Depending on the simulation outputs, the smoothed distribution pattern of the estimates of I by delete-1 jackknife is visually distinguishable from the normal density, but the smoothed pattern produced by delete-d jackknife, and logarithm- transformed smoothed patterns produced by both empirical and parametric bootstraps, matched well the corresponding normal density. Thus, the estimates of I produced by delete-1 jackknife were not used to determine the suppressive effect of wasps and insecticides. The 95% percent confidence intervals or the narrowest 95 percentiles and Z-test criterion were employed to compare the effectiveness of Trichogrammajaponicum Ashmead and insecticides （powder, 1.5% mevinphos ＋ 3% alpha-hexachloro cyclohexane） against the rice leaf roller based on the estimates of I produced by delete-d jackknife and bootstrap techniques. At a = 0.05 level, there were statistical differences between wasp treatment and control, and between wasp and insecticide treatments, if the normality is ensured, or by the narrowest 95 percentiles. However, there is still no difference between insecticide treatment and control. By Z-test criterion, wasp treatment is better than control and insecticide treatment with P-value 〈 0.01. Insecticide treatment is similar to control with P-value 〉 0.2 indicating that 95% confidence intervals procedure is more conservative. Although similar conclusions may be drawn by re-sampling techniques, such as the delta method, about the suppressive effect of trichogramma and insecticides, the normality of the estimates can be checked and guaranteed, and the correlation among sequential life stages of rice leaf roller is also considered in the estimation. Judged by the P-values from Z-test, the delta method is more conservative.展开更多
基金supported by the National Natural Science Foundation of China(32272210).
文摘To study the relationship between rice leaf color change and grain filling,two indica-japonica hybrids with distinct leaf colors were grown under three N fertilizer dosages(LN,0 kg ha^(−1);MN,150 kg ha^(−1);HN,300 kg ha^(−1)).The leaf color change features of flag leaf,2nd leaf and 3rd leaf,as well as grain filling traits of superior and inferior grains were compared.Compared to cultivar CY167(normal green leaves)under the same N level,cultivar CY927(dark green leaves)exhibited delayed leaf color change onset time(T_(0))by 0–3.6 d,reduced mean leaf color change rate(R_(m))by 1.98%–9.45%,and increased leaf color index at maturity(CI_(f))by 3.77%–53.48%.Additionally,CY927 prolonged the grain filling period(D)of inferior grains by 0.6–2.0 d,resulting in a yield increase of 8.13%–25.46%.N supply significantly increased rice yield,primarily by delaying T_(0)and reducing R_(m)of flag leaf,improving initial grain filling potential(R_(0))and maximum grain weight(A),delaying the time to reach the maximum grain filling rate(T_(max)),and prolonging the grain filling activity period(D)of inferior grains.The time interval(T_(L-G))between the T0 of the flag leaf and T_(max)of inferior grains was negatively correlated with yield(−0.780,P<0.01).Suggesting that rice yield can be improved by optimizing N fertilizer management to shorten the T_(L-G).These findings provide valuable knowledge about the relationship between leaf senescence and grain filling,and benefit the understanding of the physiological mechanisms underlying high-yield rice production.
文摘Taking a published natural population life table of rice leaf roller, Cnaphalocrocis medinalis （Lepidoptera： Pyralidae）, as an example, we estimated the population trend index, I, via re-sampling methods （jackknife and bootstrap）, determined its statistical properties and illustrated the application of these methods in determining the control effectiveness of bio- agents and chemical insecticides. Depending on the simulation outputs, the smoothed distribution pattern of the estimates of I by delete-1 jackknife is visually distinguishable from the normal density, but the smoothed pattern produced by delete-d jackknife, and logarithm- transformed smoothed patterns produced by both empirical and parametric bootstraps, matched well the corresponding normal density. Thus, the estimates of I produced by delete-1 jackknife were not used to determine the suppressive effect of wasps and insecticides. The 95% percent confidence intervals or the narrowest 95 percentiles and Z-test criterion were employed to compare the effectiveness of Trichogrammajaponicum Ashmead and insecticides （powder, 1.5% mevinphos ＋ 3% alpha-hexachloro cyclohexane） against the rice leaf roller based on the estimates of I produced by delete-d jackknife and bootstrap techniques. At a = 0.05 level, there were statistical differences between wasp treatment and control, and between wasp and insecticide treatments, if the normality is ensured, or by the narrowest 95 percentiles. However, there is still no difference between insecticide treatment and control. By Z-test criterion, wasp treatment is better than control and insecticide treatment with P-value 〈 0.01. Insecticide treatment is similar to control with P-value 〉 0.2 indicating that 95% confidence intervals procedure is more conservative. Although similar conclusions may be drawn by re-sampling techniques, such as the delta method, about the suppressive effect of trichogramma and insecticides, the normality of the estimates can be checked and guaranteed, and the correlation among sequential life stages of rice leaf roller is also considered in the estimation. Judged by the P-values from Z-test, the delta method is more conservative.
