The Preliminary Study Of Self-compatibility And Inbreeding Depression In Dendranthema×Grandiflora

Chrysanthemum is one of the ten famous traditional flowers in china and one of the four cutting flowers in word,having supernally ornamental and economic value. Chrysanthemum is deemed to belonging to sporophyte self-incompatible plant,but Anderson considered that its self-incompatibility and reproducible obstacle were incomplete and the inbreeding seed set was by 0 to 8%.We also discovered that part cultivars have self-compatibility.This study have many studies with rml-1,rml-3, 02-42-6,rml-4 and rm48-2,including self-compatibility,meiosis,capacity of pollen, pollination biology and hereditary behave of the characters of offsprings,hoping enriching self-compatibility theory of Chrysanthemum and offering theoretics gist of breeding. Mostly results like this:1 Seed set of inbred,meiosis and capacity of pollen of different cultivarsThe results revealed that rml-1,rml-3 and 02-42-6 are self-compatible cultivars, compatibility come from tubular flowers and rml-4 and rm48-2 are self-incompatible cultivars.The pollen mother cells of 5 cultivars were observed during meiosis and were basically normal,thereinto rml - 1,rml-3 and 02-42-6 were 0.93â… +23.64â…¡+0.85â…¢+0.64â…£,0.92â… +24.40â…¡+ 0.78â…¢+0.51â…£and 0.45â… + 25.04â…¡+0.36â…¢+0.55â…£on average.The chromosome configuration at metaphaseâ… of rml-4 and rm48-2 were 0.53â… +25.25â…¡+0.84â…¢+0.16â…£and 1.39â… +24.87â…¡+ 0.42â…¢+0.40â…£on average.There were little abnormal phenomena,such as chromosome bridge,lagging chromosomes and micronuclei,but frequency of abnormal phenomena was low and hadn't affect pollen formation.The pollen viability was normal,which was by 8.1%to 28.9%,and rml-1 was lowest and rml-4 was highest.The results revealed that meiosis and pollen viability haven't connection with self-compatibility.2 Self-compatibility of different eultivars and activity of antioxidant enzymes in stigma after self-pollinationSelf-pollination was conducted in a single tubular flower and single inflorescence of chrysanthemum rml-3 and rml-4,respectively.The self-compatibility of them was investigated via aniline blue stain method.The activity of the antioxidant enzymes,i.e., SOD,POD and CAT,were detected as well.The results revealed that in self-pollination test of single tubular flower,the number of the adhered and germinated pollen grains were 15 per stigma of rml-3 on average,but no adhered pollen were observed on any stigma of rml-4.In self-pollination test of single inflorescence of the rml-3,the number of the adhered and germinated pollen grains were 31 within 0.5 h to 2 h,and increased to 54 during the period of 4 h to 6 h,whereas in rml-4,only 0-3 pollens per stigma adhered and, very few of them could geminated.Neverthless.when rml-4 was pollinated with rml-3,on average,26 pollens per stigma adhered and germinated within 0.5 h,the number of adhered pollens was maximum,on average 121 grains per stigma by 4 h to 6 h.and a lots of pollen tubes entered into style.The ability of the pollen adhesion and germination implies that rml-3 is somewhat self-compatible while rml-4 self-incompatible.Activity of antioxidant enzymes of SOD,POD and CAT in self-pollinated styles of rml-3 increased to 3.65,3.04 and 2.01 times when compared with un-pollinated styles,the activity in self-pollinated styles of rml-4 increased to 3.46,2.60 and 1.65 times,while in cross pollinated styles,the activity increased to 5.23,3.12 and 2.52 times.This suggested that changes of the activity of the tioxidant enzymes probably be regulated by the genes controlling self-compatibility.3 Heritable characters of inbred offsprings of self-compatible cultivarsSelf-compatible culfivars of rml-3 and 02-42-6 were self-pollinated,and the inbred lines of I₁,I₂ and I₃ of the each cultivar were generated.Traits of selfed offsprings were observed.When compared to each parent,seed set per flower of inbred line I₁ and I₂ of rml-3 or 02-42-6 reduced 89.5%and 97.2%,and 91.2%,92.0%,respectively.Comparing with I₁,the germination rate reduced 31.4%and 57.7%in I₂ and I₃ of rml-3,while reduced 5.4%and 8.8%in I₂ and I₃ of 02-42-6.As compared to parents,in inbred lines of I_I,I₂ and I₃ of rml-3,survival rate reduced 4.5%,22.1%and 28.6%,plant height reduced 8.6%, 34.9%and 30.5%,crown width reduced 2.1%,16.4%and 14.0%,flowering rate reduced 17.9%,23.5%and 31.8%,flower number reduced 30.5%,42.8%and 59.7%,flower diameter reduced 9.4%,12.4%and 4.75%,respectively;in inbred lines of I₁,I₂ and I₃ of 02-42-6,survival rate reduced 21.3%,33.3%and 24.2%,plant height reduced 20.5%, 29.4%and 27.7%,crown width reduced 4.2%,15,8%and 34.6%,flowering rate reduced 36.1%,38.7%and 48.8%,flower number reduced 29.6%,40.0%and 76.7%,and flower diameter reduced 30.6%,31.3%and 39.9%,respectively.In addition,the average days to flowering of inbred lines of I₁,I₂,I₃ of rml-3 or I₁,I₂ of 02-42-6 were postponed by 9.4,8.9, 5.9 days and 11.9,6.4 days,respectively.It suggested that inbreeding depression was very severe in chrysanthemum.