劉 麗,孔憲輝,王旭文,王 娟,余 渝
(新疆農(nóng)墾科學(xué)院棉花研究所/農(nóng)業(yè)部西北內(nèi)陸區(qū)棉花生物學(xué)與遺傳育種重點實驗室/新疆兵團棉花遺傳改良與高產(chǎn)栽培重點實驗室,新疆石河子 832000)
【研究意義】2018年新疆棉花種植面積達(dá)到3 700多萬畝,占全國棉花種植面積的80%[1]。高產(chǎn)、優(yōu)質(zhì)的棉花品種離不開優(yōu)良親本的篩選和優(yōu)勢組合的選育。雜交棉選育周期短,增產(chǎn)效益主要來自雜種一代的雜種優(yōu)勢[2]。評價親本材料的配合力以及研究雜交組合雜種優(yōu)勢對雜交棉育種與應(yīng)用具有重要意義[3]。雜種優(yōu)勢預(yù)測技術(shù)可提高選育強優(yōu)勢雜交種的科學(xué)性和預(yù)見性,而配合力分析就是其中最重要的預(yù)測手段。在育種過程中,親本的一般配合力(General combining ability,GCA)是關(guān)鍵,兼顧組合的特殊配合力(Specific combining ability,SCA)來改善品種的農(nóng)藝性狀和品質(zhì)性狀?!厩叭搜芯窟M展】隨著棉花高產(chǎn)、高品質(zhì)育種難度的增加,雜種優(yōu)勢利用是提高單位面積產(chǎn)量、品質(zhì)的有效途徑之一,越來越受國內(nèi)外研究者的關(guān)注[4-8]。棉花雜種優(yōu)勢表現(xiàn)在產(chǎn)量、品質(zhì)、生長發(fā)育、生理生化、亞細(xì)胞結(jié)構(gòu)直至分子水平等各種層次上[9-10]。生產(chǎn)實踐表明,利用棉花雜種優(yōu)勢能夠大幅度提高纖維產(chǎn)量,改善纖維品質(zhì)和增強抗病蟲等逆境能力[11]?!颈狙芯壳腥朦c】有研究表明,陸地棉具有高產(chǎn)、優(yōu)質(zhì)、早熟、抗逆性強等雜種優(yōu)勢,但因主要經(jīng)濟性狀均為數(shù)量性狀,受微效多基因及環(huán)境影響,使得雜交棉性狀表現(xiàn)極其復(fù)雜[12]。陸地棉品種間F1代皮棉產(chǎn)量及其構(gòu)成因素表現(xiàn)出一定的正向超親優(yōu)勢,纖維長度和細(xì)度表現(xiàn)出負(fù)向超親優(yōu)勢[13];F1代中親優(yōu)勢中,以皮棉產(chǎn)量最大,單株鈴數(shù)和鈴質(zhì)量次之,子指和衣分較小[14]?!緮M解決的關(guān)鍵問題】研究選用17個早熟陸地棉品種,采用6×11的NCⅡ設(shè)計[15],組配66個雜交棉組合,通過田間試驗,評價17份親本材料的遺傳特性、分析F1代產(chǎn)量和纖維品質(zhì)的雜種優(yōu)勢和配合力,篩選雜種優(yōu)勢的最佳組合,為強優(yōu)勢組合的親本選配提供一定依據(jù)。
試驗選用17個新疆早熟陸地棉品種,包括6個父本(B1~B6)、11個母本(A1~A11),CK為新陸早61號。2016年夏季按6×11的NCⅡ設(shè)計組配不完全雙列雜交,得到66個新組合。表1
表1 供試材料來源
Table 1 Origin of experimental materials
親本Par-ents來源Origin株高Plant height始節(jié)高First fruit branch height始節(jié)位First fruit branch posi-tion果枝數(shù)Num-ber of fruit branch單株鈴數(shù)Boll number per plant籽棉產(chǎn)量Seed cotton yield衣分Lint per-cent百粒重Hun-dred-grain weight衣指Lint index長度Fiber length整齊度Fiber unifo-rmity馬克隆值Micr-onaire value比強度Fiber stre-ngth伸長率Fiber elon-gationB1125-170.0721.876.677.209.001.8041.0318.037.3031.0686.234.2432.076.87B215-7477.9330.736.007.136.272.1344.3817.907.8328.7384.674.6930.176.67B323-9086.8730.735.677.337.072.5041.7817.477.2029.7886.974.6030.336.73B442-3480.3326.475.937.806.802.4346.1917.137.9329.2685.134.8029.476.77B572-4768.0021.405.877.207.471.9742.7217.437.6030.5386.434.6430.436.87B6H6581.7330.606.936.937.272.5039.7319.537.6029.0483.974.5029.576.80A110-10178.6027.936.736.476.132.5741.2018.237.4330.8886.204.4531.906.83A219-5388.2733.536.077.077.272.4738.2518.677.2330.5687.034.5131.137.00A348-3386.7335.137.007.137.272.4343.1119.038.1031.3085.604.4631.936.80A4H1-482.2727.406.078.277.472.3043.1017.807.3031.0484.204.2530.637.00A5H7-14376.4024.075.807.336.802.1042.3517.177.4330.9786.634.3332.276.97A6惠遠(yuǎn)140366.7320.734.677.006.602.1745.7716.137.4028.5485.734.2733.076.77A7九棉2580.8023.335.608.077.332.8041.1618.407.5730.1783.774.2029.876.83A8天云113370.9323.936.137.006.732.1342.9419.178.0731.3285.303.9331.377.00A9新農(nóng)早11273.9322.275.738.607.802.5342.2817.277.5729.5684.674.0930.976.77A10新農(nóng)早11375.0729.275.676.275.071.9338.2919.837.8328.5185.775.1830.676.73A11新石H1276.6026.476.336.536.732.3043.6214.037.5729.6785.374.4330.036.80CK新陸早61號78.3332.325.676.636.302.4242.7617.307.4530.5286.424.4032.476.90
田間試驗于2016~2017年在新疆農(nóng)墾科學(xué)院試驗地進行。2017年試驗材料為F1組合、全部親本和對照。試驗采用隨機區(qū)組設(shè)計,雙行區(qū),3次重復(fù);行長5 m,行距30+60 cm,株距10 cm,播種密度22.23×104株/hm2,田間管理同大田。
試驗分小區(qū)收花計產(chǎn)(kg/小區(qū));田間調(diào)查取樣,每小區(qū)隨機選取連續(xù)正常生長植株10株(邊行5株,中間行5株),調(diào)查株高、始果節(jié)位、始果節(jié)高、結(jié)鈴數(shù)、果枝數(shù)等;收獲前取中部10個棉鈴考種,測定百粒重(g)、衣指、衣分(%),取混合棉樣回室內(nèi)采用HVI900檢測棉花品質(zhì),測定絨長(纖維2.5%跨距長度)、整齊度、比強度、伸長率和馬克隆值。
雜種優(yōu)勢分別基于雙親平均值(MP)和高親平均值(HP)計算。以F1和CK分別代表雜種一代和對照性狀的平均值,則中親優(yōu)勢=(F1-MP)×100%/MP,超親優(yōu)勢=(F1-HP)×100%/HP,競爭優(yōu)勢=(F1-CK)×100%/CK。利用Excel 2007和DPS軟件進行數(shù)據(jù)整理和配合力分析[15-16]。
研究表明,各組合中除始節(jié)位、衣指和伸長率在F1代無顯著差異外,其他11個性狀均達(dá)到顯著或極顯著水平,這些性狀在組合間存在真實的遺傳差異,株高、始節(jié)高、果枝數(shù)、鈴數(shù)、產(chǎn)量、百粒重、馬克隆值等7個性狀雙親的GCA和SCA方差均達(dá)到顯著水平,這7個性狀在雜交組合間的表現(xiàn)差異是加性基因和非加性基因共同作用的結(jié)果;始節(jié)位、衣分、百粒重和比強等4個性狀雙親的GCA方差達(dá)到了顯著水平,SCA均不顯著,這些性狀主要受雙親的影響較大。衣指主要受父本的影響較大,伸長率受母本的影響較大,整齊度受母本的GCA和SCA的影響。在這些性狀上應(yīng)有選擇地加強對親本的選配和優(yōu)良雜交組合的篩選。表2
表2 F1代14個性狀親本GCA及雜交組合SCA方差
Table 2 The parents GCA and cross combination SCA anova of 14 traits
性狀Traits株高Plant height始節(jié)高First fruit branch height始節(jié)位First fruit branch position果枝數(shù)Number of fruit branch單株鈴數(shù)Boll number per plant籽棉產(chǎn)量Seed cotton yield衣分Lint percent百粒重Hun-dred- weight衣指 Lint index長度Fiber length整齊度Fiber unifo-rmity馬克隆值Micr-onaire value比強度Fiber stre-ngth伸長率Fiber elong-ation區(qū)組Repeat36.93 66.11 35.43 1.66 0.41 0.12 0.3271.260.32.4221.420.150.040.07??組合Comb-ination128.41??33.72??0.69 1.75??2.23??0.12??8.44??2.66??0.472.64??1.53??0.37??2.93??0.02父本P1Male parent374.82??148.37??0.47??2.78??8.59??0.28??64.71??11.52??1.07?6.55?1.870.56?6.67?0.01母本P2Female parent387.61??43.21??2.36??4.01??2.78? 0.23??11.23??4.48??0.493.99?3.19??1.29??5.35?0.04??P1×P251.93??20.36??0.38 1.19??1.49? 0.08??2.261.410.411.97??1.17?0.17??2.070.01誤差Error14.20 10.71 0.78 0.57 1.02 0.04 2.461.460.380.820.780.061.620.01
供試材料及其雜交后代變異豐富,不同性狀的遺傳力有很大的差異。大多性狀廣義遺傳力大于40%,株高廣義遺傳力可達(dá)74.28%。只有株高、衣分和馬克隆值等3個性狀狹義遺傳力大于40%。狹義遺傳力低的性狀受環(huán)境影響相對較大,始節(jié)位、衣指、整齊度指數(shù)和伸長率的狹義遺傳力很低。F1代(早代)對株高、衣分和馬克隆值等性狀的選擇效果較好。表3
F1代以籽棉產(chǎn)量的競爭優(yōu)勢、中親優(yōu)勢和超親優(yōu)勢最高,競爭優(yōu)勢平均為5.49%,中親優(yōu)勢平均為11.77%,超親優(yōu)勢平均為8.97%。14個性狀中,除株高、始節(jié)位和鈴數(shù)外,其他11個性狀的中親優(yōu)勢都為正向,表現(xiàn)出不同程度的雜種優(yōu)勢,果枝數(shù)、衣分、衣指、馬克隆值和比強的中親優(yōu)勢較大,分別為2.58%、3.55%、2.62%、2.52%和1.54%;與產(chǎn)量密切相關(guān)的果枝數(shù)、衣分、衣指等性狀在超親優(yōu)勢中也都呈明顯的正向優(yōu)勢;在競爭優(yōu)勢中,以果枝數(shù)、籽棉產(chǎn)量、衣分、百粒重、衣指和馬克隆值為正向優(yōu)勢。表3
表3 親本和F1代各性狀雜種優(yōu)勢平均值
Table 3 The heterosis average of all traits for F1generation and parents
性狀Traits親本平均表現(xiàn)Parents average組合平均表現(xiàn)F1average廣義遺傳力Broad-sense heritability狹義遺傳力Narrow-sense heritability中親優(yōu)勢Mid-parent heterosis超親優(yōu)勢Heterobeltiosis競爭優(yōu)勢Competitive advantage范圍Range平均值A(chǔ)verage范圍Range平均值A(chǔ)verage范圍Range平均值A(chǔ)verage株高Plant height77.67 76.53 74.28 51.50 -29.18~21.28-1.46 -29.34~21.00-1.69 -29.79~16.84-2.30 始節(jié)高First fruit branch height26.85 26.96 43.87 26.99 -29.23~42.271.29 -29.54~41.650.85 -41.21~15.40-15.85 始節(jié)位First fruit branch position6.08 5.50 12.72 12.72 -53.94~31.58-9.55 -54.67~29.49-10.99 -50.59~29.17-2.96 果枝數(shù)Number of fruit branch7.26 7.44 41.95 20.89 -33.86~35.032.58 -33.94~34.862.45 -27.64~32.3112.24 單株鈴數(shù)Boll number per plant7.24 6.26 40.34 19.61 -44.75~35.35-3.51 -47.67~28.20-18.08 -36.51~35.71-0.60 籽棉產(chǎn)量Seed cotton yield2.28 2.55 40.22 21.35 -12.31~53.4511.77 -14.50~49.618.97 -17.24~30.955.49 衣分Lint percent42.32 43.83 49.28 49.28 -14.23~27.833.55 -14.87~26.882.78 -15.10~26.532.50 百粒重Hundred-grain weight17.86 17.82 24.61 24.61 -28.31~25.450.09 -28.56~25.02-0.25 -26.01~29.483.31 衣指Lint index7.58 7.78 8.40 5.91 -78.90~23.942.62 -78.92~23.832.53 -78.52~26.174.47 長度Fiber length29.98 30.13 43.83 17.27 -31.46~9.840.48 -32.02~8.93-0.34 -32.66~7.91-1.28 整齊度Fiber uniformity85.52 85.80 25.41 12.86 -2.72~3.130.32 -2.77~3.080.27 -3.72~2.06-0.72 馬克隆值Micronaire value4.48 4.59 63.36 42.70 -21.81~23.982.52 -23.58~21.180.20 -20.45~26.144.30 比強度Fiber strength30.80 31.27 40.4515.35-11.03~19.161.54 -12.34~17.410.05 -15.61~13.04-3.68 伸長率Fiber elongation6.82 6.87 12.849.71-3.28~5.520.71 -3.84~4.900.13 -4.35~4.35-0.40
2.4.1 親本的GCA
研究表明,在籽棉產(chǎn)量上,母本A6的GCA最大,父本B1、B3、B4,母本A4、A7、A9和A10的GCA都為正值,用這些親本較易配出高產(chǎn)組合。母本A8的株高、百粒重、衣指和纖維長度的GCA最大,在選擇這些性狀上可以考慮用親本A8來組配。母本A10的比強的GCA最大。父本B4的衣分的GCA最大。產(chǎn)量性狀GCA好的親本是B3、B4、A4、A6、A9;品質(zhì)性狀GCA好的親本是B1、B3、A5、A8。表4
表4 親本GCA效應(yīng)值
Table 4 GCA of parents in different traits
親本Parents株高Plant height始節(jié)高First fruit branch height始節(jié)位First fruit branch position果枝數(shù)Number of fruit branch單株鈴數(shù)Boll number per plant籽棉產(chǎn)量Seed cotton yield衣分Lint percent百粒重Hundred-grain weight衣指Lint index長度Fiber length整齊度Fiber unif-ormity馬克隆值Micro-naire value比強度Fiber strength伸長率Fiber elong-ationB1-3.20-1.650.06-0.060.530.05-1.100.23-0.060.370.14-0.140.49-0.01B2-0.721.430.10-0.19-0.44-0.020.73-0.48-0.13-0.02-0.29-0.07-0.010.02B34.761.980.000.110.530.11-0.900.18-0.030.350.160.000.500.02B41.120.550.050.540.250.072.31-0.810.34-0.68-0.220.23-0.47-0.01B5-4.50-3.48-0.23-0.18-0.20-0.070.31-0.01-0.140.350.310.050.04-0.01B6-2.461.170.02-0.22-0.67-0.14-1.350.880.02-0.37-0.10-0.07-0.55-0.02A13.51-1.11-0.10-0.070.80-0.06-0.930.26-0.17-0.110.71-0.200.540.06A27.020.10-0.10-0.52-0.37-0.01-1.15-0.03-0.160.080.170.170.130.03A31.073.750.42-0.89-0.42-0.120.230.370.130.060.00-0.06-0.26-0.06A4-1.120.940.100.650.040.050.61-0.36-0.010.000.25-0.15-0.310.00A5-3.970.22-0.010.09-0.28-0.030.430.060.210.100.280.250.620.03A61.69-0.390.190.640.440.28-0.53-0.30-0.080.36-0.47-0.37-0.370.00A7-1.390.200.26-0.170.100.021.28-0.59-0.15-0.100.340.350.360.04A8-10.44-2.480.320.380.13-0.17-0.680.950.281.09-0.22-0.240.150.00A9-2.45-0.97-0.52-0.210.230.030.910.080.16-0.77-0.750.09-1.00-0.10A101.510.33-0.77-0.18-0.380.04-0.440.38-0.13-0.370.080.420.71-0.01A11-4.60-0.580.200.28-0.28-0.040.27-0.81-0.08-0.35-0.37-0.24-0.570.00
2.4.2 雜交組合的SCA
研究表明,供試組合SCA在不同性狀上各不相同。籽棉產(chǎn)量SCA最高的組合是A1×B4,衣分為A1×B2,長度為A11×B4,比強為A10×B5,鈴數(shù)為A9×B3,果枝數(shù)為A8×B2。株高SCA最低的為A4×B3,始節(jié)高SCA最低的為A2×B5,始節(jié)位SCA最低的為A9×B5,馬克隆值SCA最低的為A8×B1。
從產(chǎn)量和品質(zhì)性狀綜合來看,A1×B5、A3×B1、A4×B1、A8×B1等組合具有較大利用潛力。
兩個GCA高的親本組合不一定能產(chǎn)生SCA高的雜交組合;同一親本組配不同親本時,雜交組合的SCA效應(yīng)值會有較大的變化;在選擇高產(chǎn)組合時,應(yīng)注重選擇GCA的高的親本,要選擇至少一個GCA高的材料作親本,同時兼顧SCA的選擇。在雜交育種時,同時注重親本的GCA和組合的SCA。表5
雜交棉育種的目的是通過不同親本間的雜交,選育出在農(nóng)藝性狀、產(chǎn)量性狀和品質(zhì)性狀上能優(yōu)于其親本的雜交組合[16]。配合力是雜交組合中親本各性狀配合能力的一個指標(biāo),在育種工作中可以作為選配親本的依據(jù)。親本的GCA是后代的遺傳基礎(chǔ),而SCA是發(fā)揮雜種優(yōu)勢,配制強優(yōu)勢組合的關(guān)鍵[17]。試驗對親本材料的GCA和雜種優(yōu)勢進行研究,為篩選高優(yōu)勢組合提供了依據(jù)。
表5 各組合SCA效應(yīng)值
Table 5 SCA of hybrids in different traits
組合Combi-nation株高Plant height始節(jié)高First fruit branch height始節(jié)位First fruit branch position果枝數(shù)Number of fruit branch單株鈴數(shù)Boll number per plant籽棉產(chǎn)量Seed cotton yield衣分Lint percent百粒重Hundred-grain weight衣指 Lint index長度Fiber length整齊度Fiber unifo-rmity馬克隆值Micro-naire value比強度Fiber strength伸長率Fiber elong-ationA1×B16.232.21-0.53-0.32-0.17-0.07-0.29-0.21-0.010.98-0.510.060.13-0.01A1×B2-5.13-0.680.50-0.32-0.36-0.222.840.07-0.11-1.67-1.81-0.04-2.44-0.13A1×B32.400.31-0.06-0.021.20-0.20-1.031.360.441.121.440.211.230.04A1×B45.572.070.02-0.05-0.050.51-0.370.16-0.22-1.860.810.01-0.340.04A1×B50.12-1.57-0.330.800.000.12-0.60-0.83-0.100.450.65-0.180.850.07A1×B60.82-2.350.33-0.15-0.63-0.15-1.58-0.30-0.170.880.12-0.251.100.02A2×B1-1.750.800.47-0.60-0.830.110.390.280.10-0.06-0.30-0.09-0.33-0.07A2×B21.694.910.170.330.880.08-1.84-0.41-0.23-0.200.860.070.770.11A2×B33.622.23-0.20-0.290.140.02-0.46-0.40-0.321.06-0.62-0.14-0.27-0.02A2×B40.793.06-0.21-0.20-0.14-0.07-0.120.550.160.730.150.04-0.20-0.02A2×B510.68-10.78-0.40-0.88-0.89-0.040.42-0.010.18-1.280.090.17-0.28-0.06A2×B6-5.03-0.220.001.130.84-0.100.37-0.04-0.05-0.170.000.120.440.08A3×B11.470.01-0.250.500.100.09-0.58-0.76-0.380.080.56-0.040.33-0.06A3×B21.92-0.940.38-0.17-0.230.050.45-0.350.01-0.03-0.04-0.080.660.06A3×B30.711.110.28-0.56-0.300.16-0.430.260.01-0.23-0.16-0.10-1.100.01A3×B42.480.470.66-0.89-0.15-0.170.140.980.210.28-0.420.100.620.06A3×B54.030.500.200.620.16-0.03-0.060.390.430.77-0.210.31-0.19-0.08A3×B6-0.61-1.15-0.39-0.400.43-0.100.60-0.15-0.14-0.820.26-0.24-0.57-0.07A4×B13.06-2.850.001.200.630.120.040.580.390.750.41-0.151.410.09A4×B20.17-3.53-0.300.560.34-0.040.800.150.250.08-0.460.190.610.00A4×B3-5.640.590.270.64-0.83-0.100.17-0.74-0.16-1.020.780.01-0.670.01A4×B43.74-1.050.39-0.900.12-0.03-0.51-0.22-0.260.61-0.10-0.21-0.75-0.06A4×B50.293.710.00-0.72-0.700.040.19-0.45-0.07-0.67-0.560.00-0.67-0.03A4×B68.383.13-0.14-0.140.430.01-0.190.32-0.170.250.180.02-0.25-0.02A5×B16.50-1.19-0.09-0.47-0.18-0.140.68-0.58-0.320.240.25-0.05-0.590.02A5×B20.622.120.14-0.610.060.16-0.65-0.64-0.160.630.15-0.090.050.00A5×B3-0.26-1.030.110.11-0.170.070.54-0.200.24-0.48-0.160.211.430.08A5×B42.18-2.86-0.340.73-0.02-0.190.430.620.000.67-0.030.28-0.090.04A5×B5-1.672.300.000.310.09-0.05-0.390.560.26-0.24-0.390.03-1.27-0.13A5×B62.630.650.180.020.220.15-0.280.300.19-0.720.45-0.141.080.01A6×B10.640.550.45-0.22-1.23-0.21-0.46-0.09-0.100.60-0.490.110.240.05A6×B23.59-0.170.41-0.100.07-0.01-1.200.05-0.170.27-0.09-0.490.910.04A6×B32.350.18-0.290.640.370.230.71-0.34-0.06-0.150.28-0.30-2.00-0.02A6×B44.060.480.050.410.250.30-0.210.780.12-0.52-0.57-0.010.44-0.03A6×B5-0.932.110.33-0.57-0.30-0.160.66-0.010.210.45-0.100.120.16-0.03A6×B60.30-3.14-0.560.470.83-0.16-0.12-0.71-0.09-0.290.510.19-0.12-0.02A7×B10.860.36-0.290.18-0.230.150.740.040.10-0.500.500.37-0.560.01
續(xù)表5 各組合SCA效應(yīng)值
Table 5 SCA of hybrids in different traits
組合Combi-nation株高Plant height始節(jié)高First fruit branch height始節(jié)位First fruit branch position果枝數(shù)Number of fruit branch單株鈴數(shù)Boll number per plant籽棉產(chǎn)量Seed cotton yield衣分Lint percent百粒重Hundred-grain weight衣指 Lint index長度Fiber length整齊度Fiber unifo-rmity馬克隆值Micro-naire value比強度Fiber strength伸長率Fiber elong-ationA7×B26.040.81-0.06-0.42-0.33-0.09-1.330.42-0.040.530.19-0.220.91-0.01A7×B31.03-2.44-0.55-0.22-0.100.021.07-0.60-0.09-0.070.310.180.800.04A7×B4-0.391.560.520.45-0.01-0.070.460.18-0.140.040.150.11-0.03-0.01A7×B53.89-1.580.60-0.430.500.00-0.51-0.050.18-0.240.05-0.130.16-0.01A7×B6-1.421.280.310.280.170.000.75-0.58-0.160.14-0.870.04-0.920.00A8×B12.110.64-0.020.431.410.04-2.040.20-0.360.060.75-0.55-0.480.05A8×B26.09-1.58-0.461.59-0.190.071.06-0.330.141.30-0.450.13-0.01-0.03A8×B3-0.79-1.260.050.31-0.99-0.29-1.330.00-0.261.00-0.26-0.170.63-0.02A8×B44.121.170.19-0.63-0.04-0.090.510.530.19-1.08-0.200.370.08-0.03A8×B5-5.232.871.07-0.850.010.050.820.710.45-0.510.540.09-0.460.00A8×B63.70-1.85-0.16-0.47-0.190.220.20-0.160.120.32-0.61-0.110.390.01A9×B1-2.75-2.130.490.03-0.950.040.50-0.600.02-0.03-0.980.070.33-0.01A9×B2-0.971.98-0.28-0.98-0.650.030.370.51-0.05-0.790.02-0.02-0.50-0.06A9×B35.42-0.360.36-0.291.65-0.130.47-0.100.08-0.52-0.89-0.07-0.17-0.09A9×B4-4.14-1.93-0.480.630.460.01-0.280.21-0.020.180.34-0.130.030.04A9×B510.480.80-1.200.680.850.150.19-0.250.10-0.57-0.260.07-0.39-0.03A9×B61.971.650.09-0.28-1.35-0.11-0.450.320.030.961.020.16-0.300.04A10×B1-3.97-0.53-0.47-0.47-0.140.030.550.040.34-1.070.560.490.26-0.10A10×B21.87-2.92-0.37-0.610.090.16-0.050.640.61-0.090.290.13-0.54-0.02A10×B39.602.840.340.18-0.210.07-1.530.70-0.060.36-0.460.230.830.01A10×B4-1.23-1.53-0.610.500.41-0.19-0.07-0.990.27-0.370.18-0.32-0.44-0.05A10×B51.520.60-0.530.580.32-0.12-0.53-0.12-1.781.20-0.32-0.351.910.18A10×B62.221.550.13-0.37-0.480.051.090.120.49-0.39-0.180.24-1.30-0.04A11×B15.942.140.24-0.261.59-0.160.481.090.23-1.05-0.76-0.22-0.76-0.15A11×B22.45-0.01-0.130.730.33-0.19-0.46-0.10-0.27-0.021.340.41-0.420.04A11×B3-0.09-2.16-0.30-0.49-0.770.150.710.060.18-1.08-0.26-0.04-0.70-0.02A11×B41.15-1.46-0.08-0.06-0.82-0.010.03-2.80-0.311.33-0.31-0.220.670.01A11×B5-4.831.030.270.46-0.040.03-0.200.070.140.630.50-0.120.190.13A11×B65.390.450.43-0.10-0.280.19-0.380.87-0.06-0.16-0.89-0.040.45-0.02
配合力是親本的一種內(nèi)在屬性,受多種基因效應(yīng)支配[18]。GCA主要是由基因的加性效應(yīng)決定的,是可遺傳的部分[19]。GCA高的性狀,其遺傳力也高,且受外界環(huán)境的影響較小,所以通過GCA的測定,可以反映親本的利用價值,預(yù)測雜種后代的表現(xiàn)[20]。一般來說,果枝數(shù)、鈴數(shù)、籽棉產(chǎn)量、衣分、長度、整齊度、比強等性狀的GCA越高越好,而株高、始節(jié)高、始節(jié)位、馬克隆值等性狀的GCA越低越好。研究分析了17個早熟陸地棉為親本的GCA,其中母本A6和父本B3的在籽棉產(chǎn)量上的GCA最大,衣分GCA效應(yīng)最大的為父本B4;纖維品質(zhì)性狀GCA較大的為母本A8和父本B1,在組配高產(chǎn)優(yōu)質(zhì)的組合時首先考慮這些GCA效應(yīng)較大的親本。
SCA是兩個親本雜后通過相互作用才能表現(xiàn)的非加性效應(yīng),即基因的顯性和上位性效應(yīng),是不能穩(wěn)定遺傳的[21]。在供試組合中,F(xiàn)1籽棉產(chǎn)量SCA較優(yōu)的組合為A1×B4、A6×B3和A6×B4,在試驗中,其籽棉產(chǎn)量比對照新陸早61號分別超出29.9%、31%和32.4%,說明通過不完全雙列雜交進行雜種優(yōu)勢研究可篩選到高產(chǎn)優(yōu)勢的組合,這些組合可在雜交棉的選育中加以利用。通過對親本和雜交組合各性狀的GCA和SCA分析發(fā)現(xiàn),雙親GCA和組合SCA相互獨立,組合SCA與其親本GCA效應(yīng)并不對應(yīng),親本GCA高的性狀,組合SCA不一定高;親本GCA低的性狀,組合SCA并不一定低,進一步說明不同棉花品種間存在GCA和SCA差異,需要通過篩選來獲得具有競爭優(yōu)勢的新組合[17]。研究結(jié)果中,從產(chǎn)量和品質(zhì)性狀綜合來看,A1×B5(10-101×72-47),A3×B1(48-33×125-1),A4×B1(H1-4×125-1),A8×B1(天云1133×125-1)等組合具有較大利用潛力。
雜種優(yōu)勢是自然界普遍存在的一種生物學(xué)現(xiàn)象[22-24],已經(jīng)在農(nóng)業(yè)生產(chǎn)上得到廣泛的應(yīng)用。雜種優(yōu)勢的產(chǎn)生主要有兩個原因,一是超顯性;二是基因效應(yīng)的分散性,即增效基因分散在不同的親本中,不同位點顯性基因效應(yīng)互補[21]。研究表明,棉花產(chǎn)量等性狀存在明顯的中親雜種優(yōu)勢,競爭雜種優(yōu)勢是具有直接經(jīng)濟意義的衡量標(biāo)準(zhǔn),即“有用雜種優(yōu)勢”[10]。研究通過雜種優(yōu)勢分析發(fā)現(xiàn),F(xiàn)1的產(chǎn)量性狀和品質(zhì)性狀都有不同程度的中親優(yōu)勢、超親優(yōu)勢和競爭優(yōu)勢,但值得注意的是馬克隆值的競爭優(yōu)勢明顯,F(xiàn)1的馬克隆值較高,帶來新的問題,棉花紡織工業(yè)所期望的馬克隆值不超過5.0,但就目前新疆雜交棉品質(zhì)來看,馬克隆值較高已成為亟待解決的問題之一。這就需要加強親本GCA選擇外,還應(yīng)注重SCA的選擇,以及考慮綜合性狀表現(xiàn)[17]。
4.1 供試材料及其雜交后代變異豐富,不同性狀的遺傳力有很大的差異。F1代對株高、衣分和馬克隆值等性狀的選擇效果較好。F1代籽棉產(chǎn)量的競爭優(yōu)勢、中親優(yōu)勢和超親優(yōu)勢最高。
4.2 產(chǎn)量性狀GCA好的親本是B3(23-90),B4(42-34),A4(H1-4),A6(惠遠(yuǎn)1403),A9(新農(nóng)早112);品質(zhì)性狀GCA好的親本是B1(125-1),B3(23-90),A5(H7-143),A8(天云1133)。
4.3 供試組合SCA在不同性狀上各不相同。從產(chǎn)量和品質(zhì)性狀綜合來看,A1×B5(10-101×72-47),A3×B1(48-33×125-1),A4×B1(H1-4×125-1),A8×B1(天云1133×125-1)等組合具有較大利用潛力。