Floral Organ Variations And Cloning The Genes For Floral Development In Precocious Walnut (Juglans Regia L.)

Precocious walnut is a rare natural resource which seedling from sowing to flowering and fruiting only required one or two years. In this research, the character of flowering and floral organ variation in walnut F1 hybrids of cross between precocious parent and later mature parent were observed. And the MADS-box genes relationgship with flowering process jrAP1 ,EST sequence of jrSEP1 and jrNEF1 were cloned from floral buds of precocious walunt (Juglans regia L.).The research would be offer the clues to apprehend the mechanism of tree juvenile and to accelerate the progression of walnut breeding. Main results are followed.The type and character of floral organ variation in Juglans regia L. were observed, and the anatomy of hermaphroditic development was also analyzed through paraffin section. The 2942 seedlings from cross combination were raised using 6 precocious forms, and 2 later mature forms.Among 2648 seedlings from artificial cross by precocious forms and open pollination of precocious forms, 20.34% of the seedlings were produced flowers in the third years .The 294 seedlings from later mature forms produced no flowers in the third years. 12 seedlings of the 538 precocious cross seedlings were observed on floral organ variations. The variation type includes Hermaphrodite flower, spike inflorescences, branch spike inflorescences, male and female flowers in one spike inflorescence, rosette male inflorescences. The study on floral organ variation was kept from 2003 to 2008. Stable inheritance of floral organ variation only appeared in C3 cross seedling from Xin 1×Xiangling. The floral organ variation was found in adventitious shoots of Xiangling cultivar. The anatomy of Hermaphrodite flower development procedure was: inflorescence primordium - flower primordium - bract primordium– stamen primordium - stigma primordium - ovary primordium. The floral organ variation only took place in secondor shoots and secondor flowers.According to the homologous sequences from other plants, degenerate primers were designed to amplify specific DNA fragment using cDNA prepared from floral buds of walunt. jrAP1 gene was cloned by RT-PCR through 3′RACE and 5′RACE. jrAP1 gene was 923bp.The sequence has a high identify of 76% with MADS5 gene of betula pendula and 62% with eAP1 gene of eucalyptus globulus. The jrSEP1 fragment is 112bp and has a high identify of 92% with Castanea mollissima AGL2-like gene,92% with Glycine max SEP1 and 88% with Prunus persica MADS7.The jrNEF1 fragment is 1514bp and has a high identify of 88% with Vitis vinifera hypothetical protein,83% with Populus trichocarpa predicted protein and 89% with Arabidopsis thaliana NEF1.By analysis of phylogeny construction, jrAP1 is belong to AP1 secondary family of MADS-box gene-family, jrSEP1 is belong to SEP1 secondary family of MADS-box gene-family. jrNEF1 is related to pollen wall development. The realation which the jrAP1 gene; jrNEF1 and jrSEP1 fragment with the precocious trait and floral variation in walnut was discussesed.