Studies On Eco-physiological Characters Of Conventional And Hybrid Rice Affected By Different Plant Spacing

Studies on Eco-physio1ogical Characters of Convcntionaland Hybrid Rice Affected by Different PIant spacingWang Jianlin(Shenyang Agricultural University)AbstractThe effects of seed quantity and field plant spacing on eco-physiologicalcharacters of conventional rice and hybrid rice were studied by split-split plotexperiment in the papeL And reveaIed the effects of field on the dynamic change ofch1orophyll content and tillers. heading progress' grain weight distribution. grainfilling. Iight distribution. yield components and other biologicaI characters so as toanalyze the possibility of hybrid rice in tI1e north and the technique. The results wereas follows:l. In the ear1y stage ch1orophyll content of hybrid rice was higher than that ofconventional cu1tivars. Cl1IoropI1yIl content of TiyoLI 4l8 decreased early wl1iIedecIined quickly for Liaoyou 3225 in late filling stage. Chlorophyll content wasaffected by cuItivation in early stage. ChlorophyIl content of one-seedling was vel'ysignificant1y higher than that of three-seeding in young panicle differentiatiol1.Chlorophyll content was affected by cultivars in late stage. Tl1e ratio of cI11oropl1yll Aand B was mainly decided by cuItivars and affected sIightly by p1anting conditions.2. For different seedling quantity and cultivars, dynamic in tiller was differentapparentIy. One-seeding rice had less tillers than three-seeding rice in tiller stage,while the relative increase rate was higher tl1an that of three-seeding rice. DifferentCultivars had different dynamic in tiIler. The maximum tillers and effective tiIlers ofLiaOjing 326 and Tiyou 41 8 were higher than that of Liaoyou 3225.3. Grain weigh distribution of three-seedling rice was more concentrating thanthat of one-seeding. Hybrid rice had the potential of big panicle and grain weight50distribution was more dispersed than conventional rice. One-seedling was beneficiaI tothe potential of big panicle in hybrid rice. ConventionaI cuItivars sI1ou1d be adjustedby the number ofpanicle while hybrid cultivars should be adjusted by panicIe weigl1t.4. The pre-heading stage of one-seedling rice appeared earIier tI1an that of tl1ree-seeding rice, which was due to less seeds SDwed for tI1e one seedling rice fieId Ieadingto high quality of seedling, and that did not show great correlation with tl1e seedIi11gquantity. And the earIier in equa] row spacing than in different one.5. TIlere was apparent difference in grain fiIIing character between conventionaljaponica rice and hybrid japonica rice. Grain fiIling rate of conventiona1 rice washigher tl1an that of hybrid rice and grain fi11ing stage of hybrid rice was longer tl1anthat of conventionaI rice. Tl1e difference of grain fiIIing stage happened in quickIyincreasing stagC and slowly increasing stage of grain fiIIing. The two stages of hybridrice were very significantIy Ionger than those of conventionaI rice, thus grain weigl1t' was higher. Grain filling stage was the main factor to affect grain weigl1t.6. CulturaI techniques such as seed1ing quantity. pIanting pattern etc affectedgrain weigI1t, because cuItural tecI1niques affected grain fllling rate, bLlt I1ad no effecton grain fil1ing stage.7. Two terms named semi-extinction depth and canopy IigI1t il1tensity werepointed out. They l1ad a very significant positive correlation. Semi-extinction deptl1affected Iight intensity directIy and was affected by row spacing a11d cultival.s,especially change of panicle layer.8. Leaf angle was a main factor to deterInine 1igI1t distribLltiol1 il1 booting stage.GeneralIy, the sn1alIer tI1e ]eaf angIe, tI1e better tl1e IigI1t distributiol1 .l11 fL1Il-headingstage panicIe mainly decided Iight distribution. Curved panicIe cuItivars caused l11uc]1shade so as to affect Iight distribution. Ligl1t distribution was sti1l decided by panicIein grain fiIling stage.9. For any cu]tivars, tl1e more the row spacing, the better the ligI1t distribution...