Studies On Photosynthetic Characteristics Of Barley Flag Leaf And The Quantitative Genetic Analysis Of Main Agronomic Traits

The main photosynthetic characteristics of flag leaf of different barley cultivars were studied by determining the main photosynthetic characteristics and its change trends of flag leaf during grain filling period. The quantitative inheritance of the main agronomic traits of barley were investigated using the diallel cross model with 6 parents. The results as follows:1. The diurnal variation of photosynthetic characteristics of flag leaves in flowering period: the diurnal variation curves of net photosynthetic rate of 4 cultivars were bimodal; the diurnal variation of stomatal conductance curves in cultivar Z₀₂₃Q₀₄₆R, cultivar BARI161 and cultivar G₁₁₈E₀₀₅F were basically similar, the stomatal conductance curves in cultivar 6B98-9022 was different from that of the other 3 cultivars; the diurnal variation of intercellular CO₂ in 4 cultivars are irregular, the diurnal variation curves of transpiration rate in 4 cultivars are bimodal. The diurnal variation of photosynthetic characteristics of flag leaves in grain filling period: the diurnal variation curves of net photosynthetic rate in 4 cultivars were bimodal; the diurnal variation of stomatal conductance in 4 cultivars are irregular, cultivar Z₀₂₃Q₀₄₆R showed a "V" curve; the diurnal variation curve of intercellular CO₂ in cultivar Z₀₂₃Q₀₄₆R, cultivar BARI161 and cultivar G₁₁₈E₀₀₅F showed bimodal while cultivar 4 was a single peak curve; the diurnal variation curves of transpiration rate in cultivar Z₀₂₃Q₀₄₆R and cultivar BARI161 showed bimodal while cultivar G₁₁₈E₀₀₅F was a single peak curve; the change of transpiration rate in cultivar 6B98-9022 had obvious midday depression.2. The net photosynthetic rate of flag leaf was not positively and significantly correlated with the main yield traits, indeed some yiled traits negatively correlated with the net photosynthetic rate of flag leaf.3. The chang trends of the chlorophyll concentration of flag leaf in 4 cultivars during grain fillling period were similar; The chang trends of the net photosynthtic rate of flag leaf in 4 cultivars during grain fillling period differ dramatically. Except cultivar BARI161, the chang trends of the stomatal conductance in the other 3 cultivars during grain fillling period showed a singe peak curve. The chang trends of the intercellular CO₂ in cutivar Z₀₂₃Q₀₄₆R during grain filling period showed a bimodal curve while those of the other 3 cultivars were a singe peak curve.4. Analysis of variance of the combinling ability showed that the variance of the general combinling ability of plant height, spike number, number of spike grain and weight of spike grain were significant and the variance of the combinations was dramatically significant. The analysis of the quantitative inheritance of the agronomic traits showed that the additive genetic variances of plant height, spike number and weight of spike grain were 7.65%, 36.16% and 46.71%, respectively; In phenotypic variance, the genetic variance of plant height, spike number, number of spike grain and weight of spike grain were 29.01%,66.18%,91.60% and 84.39%; The effects of environmental factors on number of spike grain and weight of spike grain were minor while the effects on plant height and spike number were relatively great.