田间免嵌合体纯化快速高效诱导枣树同质多倍体研究

Asexual polyploidization is becoming a main approach in germplasm creation of Chinese jujube, the first dry fruit tree in China, because of inefficient conventional cross breeding owing to high degree of embryo abortion. However, the existing asexual polyploidization methods behave by showing chimera, difficult purification or long growing duration. In former study, we tested callus inducement on cut section of trunk and cochicine treatment on callus and pure lignified tetraploid branches were acquired in the experimental year, which could give fruits or be propagated by grafting in the next year. Genotype,colchicine induction period, concentration and time significantly influenced the efficiency of pure polyploid induction. In this study, endogenous hormone detection and anatomical observation will be dynamically conducted during callus development and bud regeneration on different genotypes aiming to reveal regulating mechanism of bud regeneration,based on which growth regulators will be employed to regulate callus development and bud regeneration. Before callus differentiation, chromsome number of callus cells will be duplicated by employing colchicine as mutagenic agent,followed by bud regeneration. The effect of colchicine induction period, concentration and time on pure polyploid induction will be studied to establish new efficient method for in vivo pure polyploid induction in Chinese jujube combining with efficient bud regeneration technique.The newly established method will be applied on polyploid induction of large scale of Chinese jujube cultivars aiming to create polyploid germplasms with big fruit, rich nutrition, high resistance and potential usage and will be beneficial to polyploid breeding of other fruit trees and woody plants.

枣树为我国第一大干果，因胚高度败育致使常规杂交育种进展缓慢，无性多倍化成为种质创新的重要途径，但现有无性多倍化方法存在嵌合现象严重、纯化困难、生长周期长等问题。我们前期研究发现，田间截干诱导愈伤组织，秋水仙素处理愈伤后经过芽再生，可获得同质四倍体，当年木质化，翌年可结果和嫁接扩繁；基因型、秋水仙素诱变时期、浓度和处理时间对同质多倍体诱导效率影响较大。本项目拟研究不同基因型愈伤组织和芽再生过程的解剖学和内源激素水平，揭示芽再生的激素调控机制，通过生长调节剂对芽再生进行调控；于愈伤细胞分化前利用秋水仙素对愈伤细胞进行染色体加倍并调控芽再生，重点研究秋水仙素诱变时期、浓度和处理时间对同质多倍体的诱导效果，建立田间免嵌合体纯化快速高效诱导同质多倍体的方法，并应用于枣树规模化多倍体诱导，创新一批大果、富营养、高抗性、具重要应用潜力的多倍体种质，并为其他果树和木本植物的多倍体种质创新提供有益的借鉴。

枣树为我国第一大干果，因胚高度败育致使常规杂交育种进展缓慢，无性多倍化成为种质创新的重要途径，但现有无性多倍化方法存在嵌合现象严重、纯化困难、生长周期长等问题。前期研究发现，田间截干诱导愈伤组织，秋水仙素处理愈伤后经过芽再生，可获得同质四倍体，当年木质化，翌年可结果和嫁接扩繁，而且基因型、秋水仙素诱变时期、浓度和处理时间对同质多倍体诱导效率影响较大。本项目研究了不同基因型愈伤组织和芽再生过程的解剖学和内源激素水平，初步揭示芽再生的激素调控机制；于愈伤细胞分化前利用秋水仙素对愈伤细胞进行染色体加倍并调控芽再生，重点研究了秋水仙素诱变时期、浓度和处理时间对同质多倍体的诱导效果，建立了田间免嵌合体纯化快速高效诱导同质多倍体的方法，并应用于枣树规模化多倍体诱导，创新34个具重要应用潜力的多倍体种质，本研究可为其他果树和木本植物的多倍体种质创新提供有益的借鉴。