農(nóng)學(xué)專(zhuān)業(yè)外文翻譯.doc

沈陽(yáng)農(nóng)業(yè)大學(xué)學(xué)士學(xué)位論文外文翻譯播期對(duì)優(yōu)質(zhì)脂肪酸大豆品系農(nóng)藝性狀和種子組分的影響C. L. Ray,* E. R. Shipe, and W. C. Bridges摘 要：最近大豆育種者的研究重點(diǎn)之一是開(kāi)發(fā)優(yōu)質(zhì)油用大豆，如降低棕櫚酸（16：0）和亞油酸（18：3）。一個(gè)回交育種計(jì)劃育成了5個(gè)低-（16：0），2個(gè)低-（16：0）+（18：3）及1個(gè)低-（18：3）改良脂肪酸品系。本次研究的主要目標(biāo)是：1，分析播期對(duì)這8個(gè)優(yōu)質(zhì)脂肪酸品系的脂肪酸含量的影響；2，比較這8個(gè)優(yōu)質(zhì)脂肪酸品系與普通品種的種子組分和農(nóng)藝性狀的不同。試驗(yàn)分別于2001，2003，2004年在克萊姆斯和南卡羅萊納州兩地對(duì)8個(gè)優(yōu)質(zhì)脂肪酸品系和4個(gè)對(duì)照的普通品種進(jìn)行兩個(gè)播期播種。選擇播期來(lái)模擬南卡羅萊納州大豆生產(chǎn)的一個(gè)生長(zhǎng)季和兩個(gè)生長(zhǎng)季。農(nóng)藝性狀包括籽粒產(chǎn)量、株高、倒伏性、成熟期、籽粒大小、品質(zhì)，以及籽粒的蛋白質(zhì)、油分和脂肪酸水平。播期對(duì)所有的農(nóng)藝性狀有顯著影響，同時(shí)對(duì)蛋白質(zhì)、油分、棕櫚酸和亞油酸水平有影響。晚播使棕櫚酸的含量降低，早播導(dǎo)致亞油酸水平降低?；蛐蛯?duì)所有農(nóng)藝性狀和種子成分有顯著影響。如此看來(lái)，雖然基因型可以不同程度的減少棕櫚酸和亞油酸的含量，播期也可能影響優(yōu)質(zhì)脂肪酸品系的棕櫚酸和亞油酸的減少。關(guān)鍵詞：修飾脂肪酸品系;美國(guó)農(nóng)業(yè)部國(guó)家應(yīng)用研究中心大豆油分中平均含有將近14%的飽和脂肪。棕櫚酸和硬脂酸的減少會(huì)降低大豆油中飽和脂肪水平。2006年，美國(guó)食品和藥品協(xié)會(huì)要求食品要標(biāo)明飽和、不飽和及游離脂肪酸的種類(lèi)和含量。亞油酸影響的穩(wěn)定性，味道和氣味，并且在提煉油的過(guò)程中促使了氫化作用。減少亞油酸水平將減少油的氫化作用，提高其穩(wěn)定性，改善食味和氣味。減少了氫化作用反過(guò)來(lái)也會(huì)降低大豆油中的游離脂肪酸。一般認(rèn)為大豆籽粒成分受環(huán)境因素的影響。通過(guò)在不同地區(qū)和年份種植，大豆籽粒的組分也不同。通過(guò)多點(diǎn)多年試驗(yàn)，大豆籽粒組分的不同可能是由于氣候條件的不同。有人認(rèn)為溫度是對(duì)大豆籽粒成分影響最大的環(huán)境因素。在大豆籽粒成熟過(guò)程中的油分積累階段（R5-R6生長(zhǎng)時(shí)期）高溫會(huì)導(dǎo)致油分含量的升高和蛋白質(zhì)含量的降低（P、B1999）。在大豆籽生長(zhǎng)發(fā)育過(guò)程中溫度條件被認(rèn)為對(duì)不飽和脂肪酸的組分有最大的影響（H、C1957，S、R1978）。從一項(xiàng)在美國(guó)南部和Puerto Rico兩地的關(guān)于減少棕櫚酸種質(zhì)的研究結(jié)果，可以看出棕櫚酸含量的多變性。它的大多易變性都和生長(zhǎng)期間的最低溫度的變化有關(guān)。Cavrer等人在1986年的研究結(jié)果表明將大豆種在較溫暖的環(huán)境下，籽粒中油酸、亞油酸及亞麻酸的水平都有所提高。與飽和脂肪酸和單不飽和脂肪酸相比，低亞麻酸含量的品系對(duì)環(huán)境的改變反應(yīng)越來(lái)越不靈敏。直覺(jué)判斷，這些研究結(jié)果表明播期可能影響一個(gè)大豆基因型的脂肪酸的構(gòu)成。播期的不同影響植株在籽粒成熟期油分積累階段的溫度以及生長(zhǎng)季的長(zhǎng)度。T等人在1979年的研究結(jié)果是，大豆籽粒的脂肪酸組分也受生長(zhǎng)時(shí)期長(zhǎng)度的影響。光周期促進(jìn)大豆生長(zhǎng)和成熟的生理進(jìn)程。播期影響生長(zhǎng)階段的長(zhǎng)度，它決定了成熟前植株的發(fā)育天數(shù)。W等人的研究結(jié)果表明，晚播可能使棕櫚酸和亞麻酸的含量下降，而使硬脂酸的水平略微升高。這個(gè)研究也表明了在大豆籽粒成熟的最后20天，亞油酸含量隨溫度的升高而升高。S等人的研究結(jié)果表明播期對(duì)一些不同的基因型和年份的大豆的脂肪酸水平有很大影響。通過(guò)不同年份的結(jié)果平均值表明，播期對(duì)改良棕櫚酸結(jié)構(gòu)的基因型品沒(méi)有產(chǎn)生顯著的不同影響。與w等人的結(jié)論相反，s等人的結(jié)果是在籽粒成熟的最后20天溫度不能對(duì)籽粒成分的不同做出最后的解釋。O等人2006年對(duì)13個(gè)有改良油酸結(jié)構(gòu)的基因型品種及4個(gè)普通品種在10個(gè)不同環(huán)境下進(jìn)行了穩(wěn)定性分析。他們復(fù)原了在大豆生殖生長(zhǎng)的最后30天的平均溫度下的脂肪酸水平。他們發(fā)現(xiàn)，所有品種的油酸含量隨溫度的升高而升高，亞麻酸的含量隨溫度的升高而降低。不同基因型品種的油分的穩(wěn)定性不同，如中等含量的油酸基因型品種沒(méi)有油酸含量更低的品種穩(wěn)定。他們還聲明，與亞麻酸含量正常的品系相比，亞麻酸含量最低品系的亞麻酸含量受溫度變化的影響較小。常規(guī)品種的天然大豆油一般含有10%的棕櫚酸（16：0），4%的硬脂酸（18：0），22%的油酸（18：1），54%的亞油酸（18：2）及大約10%的亞麻酸（18：3）。至少兩個(gè)隱性等位基因控制低-16：0的性狀表達(dá)。這兩個(gè)等位基因結(jié)合的結(jié)果是低于4%16:0,從而降低飽和脂肪酸水平。至少兩個(gè)隱性等位基因控制低-18：3的性狀表達(dá)。這兩個(gè)等位基因結(jié)合的結(jié)果是低于3%18:3。提煉油時(shí)，低-18：3的油自然有優(yōu)于氫化大豆油的氧化穩(wěn)定性和食味特征。美國(guó)農(nóng)業(yè)部大豆基因組計(jì)劃通過(guò)讓兩個(gè)低-16：0品系和一個(gè)低-18：3品系的雜交，意圖通過(guò)理想脂肪酸性狀的回交得到更高產(chǎn)和更好的農(nóng)藝性狀。Hagood和Maxcy被用作適合的輪回親本。Dillon和一個(gè)低-18：3品系雜交。共得到了8個(gè)改良脂肪酸體系。這個(gè)研究的目標(biāo)是：1，分析播期對(duì)這8個(gè)改良脂肪酸品系的脂肪酸含量的影響；2，將它們與其親本品系（Dillon、Maxcy、Hagood）的籽粒組分和農(nóng)藝性狀比較。迄今為止，對(duì)于適合美國(guó)中南部種植地區(qū)的大豆種質(zhì)，播期對(duì)其籽粒成分的影響還沒(méi)有被研究清楚。材料與方法（略）結(jié)果與討論種子組分 不同的播期對(duì)種子組分有顯著性差異，硬脂酸，油酸和亞油酸除外（見(jiàn)表2）。不同年份和不同播期的平均計(jì)算表明基因型對(duì)七個(gè)品系的種子組分有顯著性影響。播期和基因型對(duì)棕櫚酸，硬脂酸，油酸，亞油酸，亞麻酸，氨基酸的互作效應(yīng)顯著。播期、基因型、和年份的互作對(duì)蛋白質(zhì)、油酸、亞油酸的影響顯著。大多變量之間存在互作效應(yīng)，他們沒(méi)有得到基因型水平的顯著改變的結(jié)論。播期影響溫度對(duì)不同基因型品系在籽粒充實(shí)階段的影響最大。籽粒充實(shí)階段是指生理成熟前4周。對(duì)于早期播種的植株，溫度介于籽粒充實(shí)階段第一周的26-28到最后一周的21-23。對(duì)于播種較晚的溫度范圍在22-24籽粒充實(shí)階段第一周和19-21最后一周。播期和基因型對(duì)種子蛋白質(zhì)的影響顯著。不同基因型品系的蛋白質(zhì)平均水平在388-419g/kg之間，這在當(dāng)前利用的商業(yè)品種的正常范圍之內(nèi)。早播使不同基因型品種有顯著較高的蛋白質(zhì)含量，但是僅僅高了4g/mg。在不同年份和播期下MFAL SC01-51品系的平均蛋白質(zhì)含量最高(419 g kg1)。通常修飾脂肪酸體系的蛋白質(zhì)含量水平均在可接受的范圍之內(nèi)，但是有一例外就是他們均超出其親本的蛋白質(zhì)含量水平。MFAL SC9636-1756一個(gè)low 16:0 Maxcy衍生系是MFAL中唯一一個(gè)蛋白質(zhì)含量沒(méi)有超越親本的品種。在相同年份和基因型，播期對(duì)籽粒油分含量由很大的影響；在相同年份和播期下，不同基因型的油分含量也有很大不同。MFAL中的所有Maxcy衍生系的籽粒油分含量明顯低于其輪回親本。不同基因型的種子油分范圍為173 -200 g kg1,這是目前商業(yè)品種的正常范圍之內(nèi)。早播使油分含量明顯的高于晚播。通常在籽粒構(gòu)成階段升高溫度有助于種子油分含量的增加。這個(gè)結(jié)果支持了先前的一個(gè)研究即基于種子發(fā)育期間與遇高溫會(huì)增加種子的油分含量預(yù)計(jì)提前播種日期會(huì)增加種子中的油分含量。控制品種Soyola的種子的平均油分含量最高200g/kg。MFALs中的Hagood衍生系 和 Maxcy衍生系均低于其親本品種的油分含量。在相同的年份和基因型下晚播明顯降低棕櫚酸16:0水平。較晚播種日期下較低的棕櫚酸水平與先前的相繼推遲播期棕櫚酸含量趨于更低的研究一致。不同基因型的棕櫚酸水平明顯不同。選育的低棕櫚酸和18:3品系MFAL SC01-51的棕櫚酸水平最低為40.3 g/mg。和預(yù)期的一樣，選育的七個(gè)低棕櫚酸的MFAL品系的棕櫚酸水平明顯低于四個(gè)控制品種。播期對(duì)硬脂酸的影響沒(méi)有明顯的不同。而相同的年份和播期下，基因型對(duì)其的影響顯著。其中四個(gè)MFALs的硬脂酸水平比水平最低的控制品種Hagood(34.2 g kg1)的硬脂酸的水平更低?；蛐蛯?duì)staeric酸的水平影響更明顯。其中Hagood衍生系MFAL SC9631-1505的硬脂酸的水平最低(30.4 g kg1)。播期對(duì)油酸的影響沒(méi)有明顯的不同。而相同的年份和播期下，基因型對(duì)其的影響顯著。不同基因型的oleic含量范圍為258.0 -198.8g/ kg，大部分的商業(yè)品種水平都在這個(gè)范圍之內(nèi)。Soyola創(chuàng)出最高的油酸水平，而MFALSC9634-1657創(chuàng)出最低的油酸水平。通常MFALs生產(chǎn)的油酸水平均低于其親本水平。 在相同的年份和基因型下，播期對(duì)亞油酸水平?jīng)]有明顯的影響。只有一個(gè)MFAL, SC9634-1657,和 Hagood在早播下有較高的亞油酸水平。在相同的年份和播期下，基因型對(duì)亞油酸水平由顯著的影響。所有的 MFALs 的亞油酸水平均高于四個(gè)親本品種。八個(gè)MFALs的亞油酸水平介于588.2 to657.6 g kg1, 而四個(gè)控制品種則介于550.6 to 577.1 g kg1 。播期、基因型及其播期和基因型的互作均對(duì)亞油酸水平由很大的影響。晚播產(chǎn)生的最高的亞油酸水平為73 g kg1。在相同的年份和播期下，不同的基因型亞油酸水平有明顯的不同。不同基因型的亞油酸水平在93.1 - 40.4 g kg1. 以選亞油酸水平為目的選育出的MFALs SC00-1741和 SC01-51產(chǎn)生了最低亞油酸水平。這兩個(gè)品系與一個(gè)商業(yè)品種低亞油酸水平的Soyola (42.1 g kg1)的亞油酸水平相等。文獻(xiàn)出處：C. L. Ray,* E. R. Shipe, and W. C. Bridges, Jr. 2008.Planting Date Infl uence on Soybean Agronomic Traits andSeedComposition in Modifi ed Fatty Acid Breeding Lines. Crop Sci. 48:181188.外文原文Planting Date Infl uence on Soybean Agronomic Traits andSeedCompositionin Modifi ed Fatty Acid Breeding LinesC. L. Ray,* E. R. Shipe, and W. C. BridgesABSTRACTA primary focus for soybean Glycine max (L.)Merr. breeders recently has been the development of cultivars with improved oil qualities such as reduced palmitic acid (16:0) and linolenic acid (18:3). A backcross breeding program was used to develop fi ve low 16:0, two low 16:0 + 18:3, and one low 18:3 modifi ed fatty acid breeding lines (MFALs). Research objectives were (i) to determine planting date effects on fatty acid content in the eight MFALs and (ii) to compare the MFALs to parental cultivars for seed composition and agronomic traits. The eight MFALs and four control cultivars were evaluated at two planting dates at Clemson, SC, in 2001, 2003, and 2004. Planting dates were chosen to simulate full season and double crop planting dates for South Carolina soybean production.Agronomic traits including seed yield,plant height, lodging, maturity date, seed size,and seed quality were measured, and seeds were analyzed for protein, oil, and fatty acid levels. Planting date had a signifi cant effect on all agronomic variables, as well as on protein,oil, and palmitic and linolenic acid. There was a decrease in palmitic acid at the late planting date, while the early planting date resulted in a decrease in linolenic acid levels. The effect of genotype was signifi cant for all agronomic and seed composition variables measured when averaged across planting dates. It appears that planting date may be manipulated to reduce palmitic or linolenic acid of MFALs, although the extent of the reduction varies with genotype.Abbreviations: MFAL, modifi ed fatty acid breeding line; NCAUR,USDA National Center for Utilization Research.Soybean Glycine max (L.) Merr. oil contains approximately 14% saturated fat on average (Wilson, 2004). Reduction in palmitic and stearic acids will decrease the level of saturated fat in soybean oil. In 2006, the U.S. Food and Drug Administration required food labeling to include levels of saturated, unsaturated, and trans fatty acids (U.S. Food and Drug Administration,2006). Linolenic acid aff ects soybean oil stability, fl avor, and odor and drives the need for hydrogenation in the refi nement process.Reducing linolenic acid levels will reduce the need for hydrogenation of the oil and improve stability, fl avor, and odor. Reducing hydrogenation will in turn reduce trans fatty acid levels in soybean oil.Soybean seed composition is known to be affected by environmental factors. Composition of soybean seeds has been shown to diff er across environments and years (Cherry et al., 1985;McClure, 1999; Schnebly and Fehr, 1993). Diff erences in soybean seed composition are likely due to variable weather conditions that occur across locations and years (Primomo et al., 2002). It is hypothesized that temperature is the environmental factor with greatest infl uence on soybean seed composition. During the oil deposition phase (R5R6 growth stage) of seed maturation, high temperatures result in increased oil content and decreased protein content (Piper and Boote,1999). Temperature conditions during soybean seed development are considered to have the greatest eff ect on the unsaturated fatty acid composition of soybean seed (Howell and Collins, 1957; Slack and Roughan, 1978).Results from a study working with reduced palmitic acid germplasm in the southern United States and Puerto Rico indicated substantial variability in palmitic acid levels (Rebetzke et al., 2001). Much of this variability was associated with changes in minimum temperatures during the growing season. Results from Carver et al. (1986) suggested that oleic acid levels increased and linoleic and linolenic acid levels decreased when soybean was grown in warmer environments. Lines bred for reduced levels of linolenic acid tended to be less sensitive to environmental variability as compared to saturated and monounsaturated fatty acids (Carver et al., 1986).In light of such research results, it is intuitive that planting date may aff ect the fatty acid profi le of a given soybean genotype. Diff erences in planting date aff ect temperatures that a soybean crop will be subjected to during the oil deposition phase of seed maturation and length of the growing season. Results from Takagi et al. (1979) indicate that the fatty acid composition of soybean seeds is also aff ected by length of growth period. Photoperiodism is the principle physiological process that drives reproduction and maturation in soybean. Planting date infl uences length of the growing period since it dictates the number of days a crop will have for development before maturation.Results from Wilcox and Cavins (1992) suggest that palmitic and linolenic acids may decrease with later planting dates while stearic acid levels are slightly increased. Results from that study also suggest that increasing temperature during the last 20 d of seed maturation results in a concomitant decrease in the level of linolenic acid. Results from Schnebly and Fehr (1993) indicate that planting date had a signifi cant eff ect on fatty acid levels in some genotypes and years. When averaged across years, planting date did not produce signifi cant diff erences in genotypes with modifi ed palmitic acid profi les. Contrary to fi ndings by Wilcox and Cavins (1992), results from Schnebly and Fehr(1993) also provide evidence that temperatures during the last 20 d of seed maturation could not defi nitively explain differences in soybean seed composition. Oliva et al.(2006) conducted a stability analysis of 13 genotypes having modifi ed fatty acid profi les along with four commercial cultivars over 10 environments. They regressed fatty acid levels on average temperature during the fi nal 30 d of the reproductive growth period. Over all genotypes, they found that oleic acid content increased with an increase in temperature while linolenic acid content decreased with an increase in temperature. There were stability diff erences among genotypes as mid-oleic acid genotypes were less stable than were genotypes with lower levels of oleic acid. They also reported that linolenic acid in the lowest linolenic acid lines was infl uenced less by changes in temperature when compared with lines and cultivars with normal linolenic acid contents.Crude soybean oil from conventional genotypes typically contains 10% palmitic acid (16:0), 4% stearic acid (18:0), 22% oleic acid (18:1), 54% linoleic acid (18:2), and about 10% linolenic acid (18:3) (Wilson, 2004). At least two recessive alleles control expression of the low-16:0 trait in soybean (Erickson et al., 1988; Schnebly et al.,1994; Stojsin et al., 1998). When combined, these two alleles result in less than 4% 16:0, thus reducing the level of saturated fatty acid. At least two recessive alleles control expression of a low-18:3 trait in soybean (Fehr et al.,1992). Combination of these alleles results in less than 3% 18:3 in crude oil. When refi ned, naturally low-18:3 oils have oxidative stability and fl avor characteristics that are superior to hydrogenated soybean oil.Hybridizations were made with two low-16:0 lines and one low-18:3 line developed by the USDA Soybean Genetics program at Raleigh, NC, with the intent to backcross the desirable fatty acid traits into higher-yielding and improved agronomic genotypes. Adapted cultivars used as recurrent parents were Hagood (MG VII) (Shipe et al., 1992) and Maxcy (MG VIII) (Shipe et al., 1995).A cross of Dillon (MG VI) (Shipe et al., 1997) by a low 18:3 line was also made. A total of eight modifi ed fatty acid lines were developed. Objectives of the study were(i) to determine the eff ect of planting date on fatty acid content in eight modifi ed fatty acid lines (MFALs) and (ii)to compare them to parental cultivars Dillon, Maxcy, and Hagood for seed composition and agronomic traits. To date, planting date eff ects on soybean seed composition have not been investigated for germplasm adapted to the southeastern U.S. growing region.RESULTS AND DISCUSSIONSeed CompositionSignificant diff erences were recorded between planting dates for all seed composition variables except stearic, oleic,and linoleic acid levels (Table 2). Signifi cant diff erences were observed among genotypes for the seven seed composition variables measured when means were computed across years and planting dates. Signifi cant planting date by genotype interactions were observed for protein and palmitic, stearic,oleic, linoleic, and linolenic acids. Signifi cant planting date by genotype by year interactions were recorded for protein and oleic and linoleic acids. While interaction eff ects were observed for most variables they did not result in a significant change in genotype rank. Planting date had a substantial impact on the temperatures genotypes were subjected to during the seed fill phase of development (Table 3). The seed fi ll phase was considered to be 4 wk before physiological maturity. For the early planting date, temperatures ranged from 26 to 28C (7883F) in the fi rst week of seed fi ll to 21 to 23C (6974F) in the last week of seed fi ll. For the late planting date, temperatures during seed fi ll ranged from 22 to 24C (7175F) and 19 to 21C (6670F) for the fi rst and last week of seed fi ll, respectively. Significant differences for seed protein were observed for planting dates (Table 4) and genotypes (Table 2). Mean seed protein levels among genotypes ranged from 388 to 419 g kg1 (data not shown), which is within the normal range for currently available commercial cultivars (Wilson,2004). Genotypes at the early planting date had a significantly higher seed protein level than at the late planting date, but the diff erence was only 4 g kg1. The MFAL SC01-51 had the highest mean seed protein level(419 g kg1) of all genotypes across years and planting dates.Generally, modifi ed fatty acid breeding lines produced acceptable levels of seed protein and with one exception,exceeded parental cultivars for seed protein content. The MFAL SC9636-1756, a low 16:0 Maxcy derived line, was the only MFAL to have lower seed protein content than the parental cultivar. Significant differences in seed oil levels were recorded between planting dates when computed across genotypes and years (Table 4). Signifi cant diff erences in seed oil levels were also recorded between genotypes when computed across years and planting dates. All Maxcy-derived MFAL were signifi cantly lower in oil content that the recurrent parent (data not shown). Seed oil levels among genotypes ranged from 173 to 200 g kg1, within the normal range for commercially available cultivars (Wilson, 2004). The early planting date produced a signifi cantly higher mean oil level than the later planting date. Exposure to increased mean daily temperatures during seed formation generally results in increased oil content (Piper and Boote, 1999).These results tend to support the previous study since one would expect early planting dates to result in increased oil content based on increased temperatures encountered during seed development (Table 3). The control cultivar Soyola produced the highest mean oil concentration overall (200 g kg1). Oil levels were lower in Hagood- and Maxcyderived MFALs compared with recurrent parents. Later planting dates produced signifi cantly lower (p = .0519) palmitic acid levels when means were computed across years and genotypes (Table 5). Lower palmitic acid levels at the late planting date are in agreement with a previous study showing that palmitic acid levels tend to decrease with successively later planting dates (Wilcox and Cavins,1992). Significant differences for palmitic acid levels were also recorded between genotype means. The MFAL SC01-51, selected for both low palmitic and low linolenic acids,produced the lowest palmitic acid concentration (40.3 gkg1). As expected, seven MFAL selected for low palmitic acid levels produced signifi cantly lower levels of palmitic acid compared with the four control cultivars. No significant differences were observed between planting dates for stearic acid (Table 4). Signifi cant diff erences were recorded among genotypes when averaged across years and planting dates. Four MFALs produced lower levels of stearic acid than the lowest control cultivar Hagood(34.2 g kg1). The eff ect of genotype was highly significant for stearic acid. The MFAL SC9631-1505, derived from Hagood, had the lowest level of stearic aci