NL2032712B1 - Artificial hybridization breeding method of mango - Google Patents

Abstract

The present invention relates to plant hybridization breeding technology. A. method for artificial hybridization breeding of mango is proposed, characterized in comprising the following steps: (1) selection of female parent material; (2) selection of male parent material; (3) treatment of anthers; (4) castration and hybridization; and (5) sowing of hybridized, fruit. The present invention has the following outstanding substantial features and significant advances: l. non—woven bags are used in steps (1) and (2) to bag the female parent and male parent inflorescences, which solves the loss caused by the friction between the stigma and the bag during the hybridization process; 2. the anthers in step (3) are irradiated, with light, which accelerated the anther dehiscence; 3. empty shell capsules are used in step (4) to protect the stigma; 4. the present invention is simple and easy to operate, reduces the workload of hybridization, improves work efficiency, saves costs and increases the hybridization efficiency.

Description

P1497 /NLpd

ARTIFICIAL HYBRIDIZATION BREEDING METHOD OF MANGO

TECHNICAL FIELD The present invention relates to plant hybridization breeding techniques, and in particular to a hybridization breeding method of mango.

BACKGROUND Mango (Mangifera indica Linn) 1s an evergreen tropical fruit tree native to India and Southeast Asia, and is one of the well- known tropical fruits. The fruits of mangoes contain sugar, pro- tein and crude fibre. The precursor carotene of vitamin A con- tained in mango is particularly high. Vitamin C, minerals, pro- teins, fats and sugars are also main nutrients of mango. The deli- cate flesh and unique flavour of the mango have made it so popular that it is known as the "king of tropical fruits". Mangoes are widely distributed, and more than 80 countries in the world pro- duce mangoes, 90% of which are concentrated in India, Pakistan, Bangladesh, Myanmar, Malaysia and other countries in Asia; in ad- dition, mango trees are also cultivated in Brazil and Mexico in the Americas, Tanzania and Zaire in Africa, and Florida and Hawaii in the United States. It is grown in Taiwan, Guangdong, Guangxi, Hainan, Yunnan, Fujian and the Panzhihua region of Sichuan in Chi- na. Mango is one of the important fruit industries in tropical and subtropical areas, and it plays an important role in promoting poverty alleviation in poor areas, promoting agricultural struc- ture adjustment in tropical areas and increasing farmers’ income. In 2005, 132,000 hectares of mango trees were planted nationwide (excluding Taiwan), 103,000 hectares were harvested, with a pro- duction of 742,000 tonnes and an output value of 2.32 billion yu- an. More than 1,000 mango varieties exist worldwide, with the most important mango resource countries being India and the USA. Almost all varieties in India are derived from natural hybridization or genetically mutated seedlings trees, and then preserved by asexual reproduction. Except in Asia and some African countries, mango va- rieties in many countries are developed based on varieties from

Florida, USA. In recent years, India, Australia, the United States, Thailand, Mexico, Pakistan, Indonesia, the Philippines, Brazil and Nigeria are all actively engaged in variety breeding, mainly adopting live seeding selection, hybridization breeding and tissue culture techniques for variety breeding. China has carried out trials and research in the field of mango variety selection and breeding research, from seeding selection, artificial hybridi- zation breeding to mutation breeding respectively, and has achieved certain results. Since the 1980s some progress has been made in the selection and breeding of new mange varieties in Chi- na, and a number of excellent varieties that are more adaptable, late flowering, productive and stable and breeding materials have been selected, and some of the selected varieties have played a great role in the specific development stage of mango production in Guangxi and other regions of China, achieving certain economic and social benefits. However, compared with the mainly-planted va- rieties introduced from the United States, Australia and other countries, these selected excellent varieties still have a big gap in comprehensive characters such as stress resistance, yielding ability, yield stability, quality, etc., so the proportion of the extension area to the total planting area is still small. There- fore, it is urgent to carry out mango cross breeding in China. Therefore, there is an urgent need to carry out hybridization breeding of mangoes in China.

Mango is a highly heterozygous woody fruit tree. On the one hand, mango pollen is small, pollen emission and stigma acceptance time is short, stigma is short and thin; on the other hand, the growth and development of mango flowers are often affected by cli- matic conditions such as humidity and temperature, and the flower- ing periods of male parents and female parents are often incon- sistent. In addition, traditional artificial hybridization tech- niques are not mature enough, which makes mango cross pollination difficult and ineffective. In the United States, 12,000 flowers were artificially pollinated, and only 47 hybridization fruits were received. In recent years, although mango hybridization tech- nology has been improved to a certain extent, it still cannot solve some problems of mango hybridization technology. Therefore,

the establishment of a relatively simple and effective mango hy- bridization breeding method can create conditions for the creation of mango planting resources and variety improvement. The promotion of new varieties can also create favourable conditions for the de- velopment of the mango industry and for farmers to increase their income.

SUMMARY The objective of the present invention is to provide an arti- ficial hybridization breeding method of mango, which uses flower thinning, bagging, detasseling hybridization and other techniques, which has the characteristics of simple and easy operation pro- cess, high fruit setting rate, and thus can greatly improve the efficiency of mango hybridization and accelerate the process of mango hybridization. The technical solution used in the present invention is as follows: an artificial hybridization breeding method of mango, charac- terized by comprising the following steps: (1) selection of female parent material selecting a fruit tree which is in a productive stage as the female parent tree, and during the flowering stage of the mango, selecting a bearing base shoot with a sturdy branch and an inflo- rescence with most opened male flowers or some bisexual flowers as the female parent material for the hybridization, and removing the opened male and bisexual flowers with a pair of forceps, while co- vering the inflorescence with a non-woven bag to isolate the out- side pollinating medium and pollen; (2) selection of male parent material selecting fruiting tree that grows robustly as the male pa- rent tree, selecting inflorescence with most opened male flowers as male parent material, and covering the inflorescence with a non-woven bag to insulate outside pollen; the non-woven bag has the function of heat preservation and can also promote anther de- hiscence. (3) treatment of anthers before hybridization, taking down the fresh male flowers of male parent materials or male flowers and bisexual flowers whose anthers have just been dehiscent, and putting them in a glass pe- tri dish for storage; anthers that have not been dehiscent are il- luminated to promote dehiscence; (4) castration and hybridization removing the non-woven bag from the female inflorescence, and at the same time, removing the pink anthers of the bisexual flo- wers and the small flowers that have not yet opened, keeping only the bisexual flowers with the stamens removed, holding the de- hiscent anthers of the parent material with a pair of forceps, touching lightly on the stigma of the female parent material a few times to make the stigma coated with pollen, gently covering the pollinated stigma with a shell of a hollow capsule, and marking the inflorescence with a tag and a tether for later fruit picking, removing the capsules 2-3 days after hybridization; and (5) sowing of hybridized fruit when the fruit is ripe, removing the flesh and peeling off the hull to germinate the seeds for sowing, and the seedlings are transplanted in the field when they reach 20-40 cm in length.

Compared with the prior art, the present invention has the following outstanding substantive features and significant advanc- es:

1. the female and male inflorescences are bagged in advance by non-woven bags;

2. the anthers are irradiated with light, which accelerated anther dehiscence;

3. hollow capsules are used to protect the stigma;

4. the invention is simple and easy to operate, with high hy- bridization efficiency, which greatly accelerates the process of mango hybridization breeding and can save a lot of human, material and financial resources.

DESCRIPTION OF THE INVENTION Example An artificial hybridization breeding method of mango, charac- terized by including the following steps: (1) selection of female parent material generally, during full-bloom stage of mangoes from December of the current year to March of the following year, selecting a fruit tree which is in a productive stage as the female parent tree, and during the flowering stage of the mango, selecting a bearing base shoot with a sturdy branch and an inflorescence with most opened male flowers or some bisexual flowers as the female 5 parent material for the hybridization, and removing the opened ma- le and bisexual flowers with a pair of forceps, while covering the inflorescence with a non-woven bag to isolate the outside pollina- ting medium and pollen; generally, single embryo varieties are se- lected as female parents; {2) selection of male parent material selecting fruiting tree that grows robustly as the male pa- rent tree, selecting inflorescence with most opened male flowers as male parent material, and covering the inflorescence with a non-woven bag to insulate outside pollen; the non-woven bag has the function of heat preservation and can also promote anther de- hiscence.

On the one hand, the non-woven bag is light, which re- duces the pressure on the inflorescence; on the other hand, the non-woven bag has the function of heat preservation and can also promote anther dehiscence; (3) treatment of anthers before hybridization, taking down the fresh male flowers of male parent materials or male flowers and bisexual flowers whose anthers have just been dehiscent, and putting them in a glass pe- tri dish for storage; anthers that have not been dehiscent are il- luminated to promote dehiscence; ready to use when there is grey pollen dispersed; (4) castration and hybridization removing the non-woven bag from the female inflorescence, and at the same time, removing the pink anthers of the bisexual flo- wers and the small flowers that have not yet opened, keeping only the bisexual flowers with the stamens removed, holding the de- hiscent anthers of the parent material with a pair of forceps, touching lightly on the stigma of the female parent material a few times to make the stigma coated with pollen, gently covering the pollinated stigma with a shell of a hollow capsule, and marking the inflorescence with a tag and a tether for later fruit picking.

Generally selecting the flowers located above the inflorescence for hybridisation, then removing the capsules 2-3 days after hy- bridization to allow the fruit to grow under normal management conditions; and (5) sowing of hybridized fruit when the fruit is ripe, removing the flesh and peeling off the hull to germinate the seeds for sowing. Fruit maturity is usu- ally judged according to the following characteristics: the colour of the skin from green to yellowish or purplish red, fruit dots or patterns being obvious, the fruit shoulders being round and full, the flesh changing from white to yellow or orange, the hull being hardening, etc.; meanwhile, it can also be judged according to the specific gravity of the fruit: a fruit sinks into water indicating that it is mature.

Using a knife to fully remove the flesh of the fruit, drying the seeds, cutting the seeds at the pedicle of the dried seeds or peeling the shells to remove the seeds, and placing the seeds in a sand bed at intervals of 10 cm, covering the seeds with sand for 3-4 cm; setting the sand bed in a sunshelter, watering the seeds every day to keep them moist and accelerate germination, and the seeds will emerge after 5-10 days.

The nursery land is ploughed to a depth of 20 cm so as to break up the soil; adding superphosphate into animal manure for curing before ploughing and applying 3000 kg of animal manure+30 kg of superphosphate to the soil per mu(l mu=666.67 m‘), mixing evenly, then putting the mixed nutrient soil in 17 x 25 cm nutri- ent bags. Bags (polyethylene plastic bags) are buried in the soil and placed in rows with 6 bags in each row. The length depends on the plot.

When the seeds on the sand bed are germinated and exposed to the soil and then grown to 20-40 cm, the seedlings are taken out, a section of the radicle is cut off and transplanted in the nutri- ent bag. After planting, watering and shading, watering every 2-3 days until survival; when the second tips of hybridized seedlings turn green, they can be transplanted to the field. The management of the later field can refer to the normal growth management of seedlings.

In February 2010, 400 flowers were crossed by this artificial hybridization breeding method in Hainan's Oriental mango base (Jinhuang variety as the female parent and Guifei variety as the male parent), 42 hybridization seeds were obtained and 20 plants were obtained after sowing, with a hybridization efficiency of

10.53.

In February 2011, 300 flowers were crossed by this artificial hybridization breeding method in Hainan's Oriental mango base {Jinhuang variety as the female parent and Guifei variety as the male parent), 37 hybridization seeds were obtained and 36 plants were obtained after sowing, with a hybridization efficiency of

12.3% In March 2012, 20 flowers were crossed by this artificial hy- bridization breeding method (Guifei variety as the female parent and Guire 82 variety as the male parent) at the mango base of the Guangxi Nanning Tropical Crops Institute, and 4 hybridization seeds were obtained, and 4 plants were obtained by shelling and germination, with a hybridization efficiency of 20%.

Claims (1)

CONCLUSIONS An artificial hybridization breeding method of mango, characterized by comprising the following steps: (1) selection of parent female material selecting a fruit tree which is in a productive stage as the female parent tree, and during the flowering stage of the mango, the selecting a supporting basal shoot with a stout branch and an inflorescence with the most open male flowers or few bisexual flowers as the female parent material for the hybridization, and removing the open male and bisexual flowers with a tongs, while covering the inflorescence with a non-woven bag to isolate the pollination medium from the outside and the pollen; (2) selection of male parent material selecting a fruiting tree that grows robustly as the male parent tree, selecting an inflorescence with the most open male flowers as the male parent material, and covering the inflorescence with a non-woven bag to collect the pollen from the outside isolate; (3) treatment of anthers before hybridization, the fresh male flowers of the male stock or flowers and the bisexual flowers whose anthers have just dried out are removed and placed in a glass petri dish for storage; the not yet dried out anthers are illuminated to promote ejaculation; (4) castration and hybridization removal of the pellicle from the female inflorescence, and at the same time removal of the pink anthers of the bisexual flowers and the small immature flowers, keeping only the bisexual flowers with removed stamens , and holding the onthescent anthers of the parent material with tweezers and lightly touching the stigma of the female parent material a few times so that the stigma is covered with pollen, the pollinated stem- carefully cover the peel with a hollow capsule shell, and mark the inflorescence with a tag and string for later picking, remove the capsules 2 to 3 days after hybridization; and (5) sowing the hybridized fruits when the fruits are ripe, the pulp is removed and the skin is peeled off to germinate the seeds before sowing; the seedlings are planted out in the field when they are 20 to 40 cm tall.