CN104429933B - Method for screening semi-wild cotton material with high salt and alkali resistance - Google Patents

Abstract

The invention relates to a method for screening semi-wild cotton materials with high saline-alkali resistance. The method comprises the steps of: (1) using 0.4% Nacl to identify the salt tolerance of the natural population of semi-wild cotton in a greenhouse at the seedling stage, and preliminary screening More resistant semi-wild cotton material. (2) Carry out habitat identification and screening on the selected high-resistance or salt-resistance (Nacl) materials in the moderately occurring secondary saline-alkali land in Xinjiang, and transplant the surviving plants under high saline-alkali selection pressure to Hainan for selfing, Individual plants are harvested and rolled separately; then planted in divisions and self-crossed to form high-resistant strains. (3) Enter the procedure of "Xinjiang saline-alkali land identification-high pressure selection-high-resistant plants transferred to Hainan-high-resistant strains", repeat this cycle 3 times, and finally select stable and reliable high saline-alkali-resistant materials from the natural population of semi-wild cotton .

Description

A method for screening semi-wild cotton materials with high saline-alkali resistance

technical field

The invention relates to plant stress resistance physiology, in particular to a method for screening semi-wild cotton materials with high saline-alkali resistance.

Background technique

Semiwild cotton, also known as the race of upland cotton, is native to the Mexican highlands and the Caribbean in Central America. Good genes that do not have, especially stress resistance genes, such as salt-alkali resistance.

In the identification of cotton salt resistance, most but usually only consider a single salt stress (NaCl), using sand culture, hydroponics or salt stress at the seedling stage under NaCl stress, sometimes the screened high salt resistance materials cannot be used in practice The problem. Because the reality is that soil salinization and alkalization often occur at the same time, and the mixed stress of salinity and alkalinity is one of the main problems of salinization, and it is not just a single salt poisoning. For example, Xinjiang in my country is known as the world's saline-alkali soil museum. The saline-alkali soil has the characteristics of large area, many types, heavy salt accumulation, and multiple ion components. The present invention aims at the complex saline-alkali environment in Xinjiang, and adopts the method of combining single-salt identification in greenhouses with multiple selections under high saline-alkali pressure in real habitats to identify and screen semi-wild cotton materials preserved in my country. The high saline-alkali resistance semi-wild cotton material screened by this method has stable and reliable resistance, not only can endure a single salt stress (NaCl), but also can adapt to complex and changeable actual adversities (such as multi-ion poisoning, alkali stress, etc.) ), so it has more practical value and significance.

Contents of the invention

The purpose of the present invention is to explore a stable, reliable, and better screening method for highly saline-alkali-resistant semi-wild cotton, so as to make up for the shortcomings of commonly used cotton salt-resistant identification and screening methods.

The screening method according to the high saline-alkali resistance semi-wild cotton of the present invention comprises the following key steps:

(1) Treat the natural population of semi-wild cotton with a mass fraction of 0.4% Nacl stress, carry out the salt tolerance identification at the seedling stage in the greenhouse, and initially screen the semi-wild cotton materials with more than resistance;

(2) Select the secondary saline-alkali land with a total salt content of 1.2% to 1.5% on the soil surface and a pH value of 7.5 to 8.5, and re-screen the semi-wild cotton material initially screened after Nacl stress treatment;

(3) According to the emergence of semi-wild cotton in saline-alkali land, the materials with a relative emergence rate ≥ 75% and the plants that survived under high saline-alkali selection pressure were transplanted to Hainan in a certain way, and self-crossing was carried out at the flowering stage, and individual plants were harvested separately. Sub-rolling; then planting in sub-plants, self-crossing to form high-resistant strains.

(4) Put the highly saline-alkali-resistant strains screened in the saline-alkali land into the program of "Xinjiang saline-alkali land identification-high pressure selection-high-resistant plants moved to Hainan-high-resistant strains", cycled 3 times, and finally obtained from the natural population of semi-wild cotton A stable and reliable material with high salt-alkali resistance was screened out.

The advantages of the present invention are:

1. Single-salt (NaCl) identification in sand culture in greenhouse can quickly identify and screen out salt-resistant materials from large quantities of semi-wild cotton materials.

2. The multiple selection of high salinity pressure in the real habitat not only makes up for the lack of identification errors caused by the uneven distribution of salt content in the field, but also avoids the situation that the results of single-salt identification in the greenhouse cannot be well applied to the complex environment in the field.

3. Combining the identification of sand cultivation in the greenhouse and repeated screening of secondary saline-alkali land, the semi-wild cotton material with high saline-alkali resistance is stable and reliable. It can not only tolerate a single salt stress (such as NaCl), but also adapt to complex conditions. Changeable actual adversity (such as multi-ion poisoning, alkali stress), so it has more practical use value.

Description of drawings

Figure 1 shows the results of the secondary saline-alkali screening test in Korla, Xinjiang in 2013, 1: the main local species; 2: semi-wild cotton 25; 3: the main local species.

Figure 2 shows the results of the secondary saline-alkali screening test in Korla, Xinjiang in 2013, 1: the main local plant species (without emergence); 2: semi-wild cotton material broad-leaved cotton 96B; 3: semi-wild cotton material broad-leaved cotton 120; 4: The main local species (unemerged).

detailed description

Example 1 Combined hydroponics and saline-alkali land to screen semi-wild cotton with high saline-alkali resistance

1. Experimental materials

194 semi-wild cotton materials (Table 1) from 7 wild species of upland cotton, originating in Mexico, were quoted from the National Cotton Germplasm Bank of the United States by the Cotton Research Institute of the Chinese Academy of Agricultural Sciences in 2007, and are now preserved in the National Wild Cotton Germplasm Nursery.

Table 1 Test materials and their sources

2. Experimental method

2.1 Preliminary identification and screening of Nacl stress treatment in greenhouse

(1) According to the mass ratio of NaCl salt and high-temperature sterilized dry fine sand, the concentration is respectively 0% (control) and 0.4% saline sand soil, add sterilized tap water until the water content reaches 23%, fully mix well, Put it in a germination box of 19cm×14cm×12cm, spread the sand thickness (30-40) mm, sow the seeds for the test (delinted with sulfuric acid and select) evenly, and then cover with 5-10mm wet sand, cover with moisture, Place in a 28°C incubator. The experiment was repeated 3 times, with 50 seeds in each repetition.

(2) Investigate the emergence rate and relative emergence rate 10 days after sowing.

Emergence rate = number of seedlings/number of sown seeds × 100%

Relative emergence rate = emergence rate of salt water / emergence rate of control × 100%

(3) Salt tolerance grading standards are as follows:

High resistance: relative emergence rate ≥ 90.00%; resistance: relative emergence rate 75.00-89.99%; tolerance: relative emergence rate 50.00-74.99%; intolerance: relative emergence rate 0.00-49.99%.

(4) According to the above standards, 14 parts of high-salt-resistant semi-wild cotton materials such as broad-leaved cotton 32 and broad-leaved cotton 33, and 36 salt-resistant materials such as Marigold cotton 85 and broad-leaved cotton 120 were screened out for the next step Saline-alkali re-screening.

2.2 Repeated screening of secondary saline-alkali land

(1) In Korla, Xinjiang, select a saline-alkali land with a total salt content of 1.2%-1.5% and a pH value of 7.5-8.5 in the surface layer of the soil (0-20cm), and plan to perform saline-alkali habitat rehabilitation on the semi-wild cotton materials initially screened after Nacl stress treatment. screen.

(2) In mid-April, sow the main local cotton varieties in the selected saline-alkali land according to the cultivation mode and treatment method of Korla, Xinjiang, including film mulching, drip irrigation and seed treatment before sowing.

(3) After the emergence of the local main cultivars, select a cotton field with relatively uniform seedling emergence and an emergence rate of 20-30%, and place the saline-alkali-resistant semi-wild cotton materials initially screened by 0.4% Nacl between the two films of the local main cultivars. Sowing, row length 1.5m (15 holes per row, hole spacing 10cm, 2 seeds per hole), row spacing 25cm, plant spacing 10cm, experiment set 5-10 repetitions, 30 seeds per repetition. Before sowing, the seeds were develored with sulfuric acid and the germination rate was measured, and the measured germination rate was used as a blank control. The emergence of local main varieties can be used as a visual reference for the level of salinity and alkalinity in the current community.

(4) When the cotyledons of semi-wild cotton were flattened, the first seedling number survey was carried out. Seedlings that emerged but died of salt damage were not included in the number of seedlings, but seedlings that died due to insect damage should be included in the number of seedlings. Investigate once every 1 week, until the stage of 4 true leaves. Drip irrigation or watering treatment cannot be carried out during the period from the sowing of local promotion varieties to the semi-wild cotton survey.

(5) Based on the number of seedlings in the last investigation, calculate the relative emergence rate.

Emergence rate = number of seedlings/number of sown seeds × 100%

Relative germination rate = emergence rate of saline-alkali land/germination rate of control × 100%

(6) According to the emergence of semi-wild cotton in saline-alkali land, several sampling points with high relative emergence rate, sporadic emergence and no emergence were selected to take soil samples, and the soil salt content and pH value were measured respectively.

(7) According to the results of 8 soil salinity measurement and the emergence situation, the materials with a relative emergence rate ≥ 75% and the surviving plants under the high salinity selective pressure are transplanted to Hainan in a certain way, and self-crossing is carried out at the flowering stage, and the individual plants are harvested and harvested separately. Sub-rolling; then planting in sub-plants, self-crossing to form high-resistant strains.

(8) Repeat steps (1)-(7) in 2.2 next year for highly saline-alkali-resistant strains, and enter the program of "Xinjiang saline-alkali land identification-high pressure selection-high-resistant plants moved to Hainan-high-resistant strains", so Cycle for 3 years.

(9) After multiple re-screenings in secondary saline-alkali land, stable and reliable materials with high saline-alkali resistance, broad-leaved cotton 96B, broad-leaved cotton 32, Marigalante 85 and broad-leaved cotton were finally screened from the natural population of semi-wild cotton 120.

Claims (3)

1. a method for screening the semi-wild cotton material of high secondary saline-alkali resistance, is characterized in that, described method comprises the following steps: (1) The semi-wild cotton natural population is treated with NaCl stress with a mass fraction of 0.4%, and the salt tolerance identification at the seedling stage is carried out in the greenhouse, wherein the salt tolerance identification standard is: high resistance: relative emergence rate ≥ 90.00%; Resistance: relative emergence rate 75.00-89.99%; resistance: relative emergence rate 50.00-74.99%; intolerance: relative emergence rate 0.00-49.99%, select semi-wild cotton materials with resistance above; (2) Select the secondary saline-alkali land with a total salt content of 1.2% to 1.5% on the soil surface and a pH value of 7.5 to 8.5. After the emergence of the main species in the secondary saline-alkali soil habitat, select relatively uniform emergence and a 20-30% emergence rate. In a cotton field, the salt-resistant semi-wild cotton materials preliminarily screened by 0.4% NaCl were sown between the two films of the main local cultivars and set up 5-10 repetitions; (3) According to the emergence of semi-wild cotton in secondary saline-alkali land, transplant materials with a relative emergence rate ≥ 75% and plants that survived under high secondary saline-alkali selection pressure to Hainan, self-fertilize at the flowering stage, and harvest per plant separately. Separate rolling, then planting by division, self-crossing to form high-resistant strains; (4) Repeat steps (2) and (3) for the highly resistant secondary saline-alkali strains screened in the secondary saline-alkali soil, and cycle 3 times, and finally select stable and reliable high-resistance secondary saline-alkali strains from the natural population of semi-wild cotton. Saline material. 2. the method for the semi-wild cotton material of screening high resistance to secondary saline-alkali according to claim 1, is characterized in that, in step (3), when semi-wild cotton cotyledon is flat, carries out the investigation of the number of emergence for the first time, although Seedlings that emerge but die due to salt damage are not counted in the number of seedlings, but seedlings that die due to insect damage should be counted in the number of seedlings. The survey will be done once a week after that until the stage of 4 true leaves. The local popularized varieties in Hainan are sown to the semi-wild cotton survey Drip irrigation or watering treatments are not allowed during this period. 3. the method for the semi-wild cotton material of screening high resistance to secondary saline-alkali according to claim 2, is characterized in that, with the emergence number of last investigation as the criterion, calculate relative emergence rate, Emergence rate = number of seedlings/number of sown seeds × 100% Relative emergence rate = emergence rate of secondary saline-alkali land/germination rate of control × 100% Among them, according to the emergence of semi-wild cotton in secondary saline-alkali land, several sampling points with high relative emergence rate, sporadic emergence and non-emergence were selected to take soil samples, and the soil salt content and pH value were measured respectively. In this case, the materials with a relative emergence rate ≥ 75% and the plants that survived under high secondary saline-alkali selection pressure were transplanted to Hainan.