Plant breeding 植物育種

Chick-please

A neglected crop is about to get a high-tech makeover

第一段：

Pliny the elder,?a Roman administrator with a sideline in philosophy, appreciated the complexities of the chickpea.?In his master work, “Naturalis Historia”, he wrote of it: “This plant presents considerable differences in reference to size, colour, form and taste.”?One type, he reported, came in the shape of a ram’s head. Another, the Venus pea, was white, round and smooth. A third had small,?angular?seeds.

老普林尼是一位羅馬行政官員，副業(yè)研究哲學(xué)，他喜歡研究鷹嘴豆的復(fù)雜性。在他的杰出作品《博物學(xué)歷史》中，他寫道：“這種植物在大小、顏色、形狀和味道方面存在著相當(dāng)大的差異。”他記錄稱，有一種是公羊頭的形狀。另一種是維納斯豌豆，白色，圓滑。第三種的種子很小，有棱角。

第二段：

These days, chickpeas are still as varied, though the main types now recognised are the large, light-coloured Kabuli and the smaller, darker Desi.?They are grown in more than 50 countries, particularly in Asia and Africa, and contribute 11.5m tonnes of protein-rich?pulses?to the world’s food supply, making them the third most productive?leguminous?food crop, after beans and peas.?But their variety is under-exploited, and much of it is found in poorly studied “l(fā)andraces”—local varieties that have some genetic coherence but are not as selectively bred as modern?cultivars.

如今，鷹嘴豆仍然是多種多樣的，盡管現(xiàn)在公認(rèn)的主要類型是大的、淺色的卡布利和小的、深色的德西。它們生長在50多個(gè)國家（在亞洲和非洲特別多），為世界糧食供應(yīng)貢獻(xiàn)了1150萬噸富含蛋白質(zhì)的豆類，使其成為僅次于黃豆和豌豆的第三大豆科糧食作物。但它們的品種還沒有得到充分的開發(fā)，其中很多是在研究不足的“地方品種”中被發(fā)現(xiàn)的，這些地方品種具有一定的遺傳一致性，但不像現(xiàn)代品種那樣有選擇性地培育。

第三段：

Recognising this, a group of researchers from the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) and 40 other organisations, led by Rajeev Varshney of Murdoch University, in Australia, have produced a comprehensive “pan-genome” derived from the cultivated plant,?Cicer arietinum, and seven of its wild relatives, which they have now published in Nature.?One of their purposes was to identify blocks of genes, called?haplotypes, that encode particular, desirable properties, and which could be?bolted?together in various combinations to yield both better chickpeas overall, and chickpeas better suited to particular sets of circumstances.?In a world where circumstances are changing rapidly, that matters.?A study published in 2016, for example, estimated that shifts in temperature and rainfall patterns could, by 2069, decrease chickpea yield in parts of the world by almost 20%.

有人意識(shí)到這一點(diǎn)。一組研究人員（來自國際半干旱熱帶作物研究所和其他40個(gè)組織，由澳大利亞默多克大學(xué)的拉杰夫·瓦爾什尼領(lǐng)導(dǎo)），他們已經(jīng)從栽培植物鷹嘴豆及其7個(gè)野生近緣植物中制備出了一個(gè)全面的“泛基因組”，他們現(xiàn)在已經(jīng)在《自然》雜志上發(fā)表了這篇文章。他們的目的之一是鑒定稱為單倍型的基因塊，這些基因塊編碼特定的、理想的特性，并且可以以各種組合的方式栓接在一起，從而產(chǎn)生整體上更好的鷹嘴豆和更適合特定環(huán)境的鷹嘴豆。在一個(gè)環(huán)境瞬息萬變的世界里，這么做很重要。例如，2016年發(fā)表的一項(xiàng)研究估計(jì)，到2069年，氣溫和降雨模式的變化可能使世界部分地區(qū)鷹嘴豆產(chǎn)量下降近20%。

第四段：

Building on an initial map of more than 28,000 chickpea genes, published by ICRISAT in 2013, Dr Varshney’s team?sequenced?3,171 cultivated chickpeas and 195 wild examples taken from collections around the world.?That added 1,582 previously unknown genes to the list, including ones that encode responses to environmental factors such as cold, acidity and oxidative stress.?The result is the most comprehensive genetic?map of any vegetable species.

在ICRISAT2013年發(fā)布的2.8萬多個(gè)鷹嘴豆基因的初始圖譜基礎(chǔ)上，瓦爾什尼博士的團(tuán)隊(duì)對3171個(gè)栽培鷹嘴豆和195個(gè)來自世界各地的野生樣本進(jìn)行了測序。這就增加了1582個(gè)以前未知的基因，包括編碼對寒冷、酸度和氧化應(yīng)激等環(huán)境因素反應(yīng)的基因。結(jié)果是所有蔬菜物種中最全面的遺傳圖譜。

第五段：
Crucially, the samples came with useful data about the characteristics of the plants they were taken from, known in the?argot?as their?phenotype.?That allowed the team to cross-correlate between genotype and phenotype, identifying which bits of the former appeared responsible for what parts of the latter.?As a consequence, they think they have identified 24 haplotypes that do useful things like increasing seed weight, improving yield per plant and reducing the time it takes for a plant to become mature enough to flower.

至關(guān)重要的是，這些樣本提供了有用的數(shù)據(jù)，這些數(shù)據(jù)是關(guān)于它們所采集的植物的特征，在行業(yè)術(shù)語中被稱為它們的表現(xiàn)型（顯型）。這使得研究小組能夠在基因型和表現(xiàn)型之間進(jìn)行交叉關(guān)聯(lián)，確定前者的哪些部分與后者的哪些部分有關(guān)。因此，他們認(rèn)為他們已經(jīng)確定了24種單倍型，作用大，如可以增加種子重量、提高單株產(chǎn)量和縮短植物成熟開花所需的時(shí)間。

第六段：

Looking back at the original collections, they found around 80% of cultivars lacked these beneficial blocks of genes, suggesting there was considerable room for improvement.?Knowing exactly which genes are involved means the process of breeding in those improvements can be done quickly.?Instead of waiting for a plant to grow and mature, you can check its genes shortly after it has germinated, and throw it away if you do not want it.

回顧最初的收集，他們發(fā)現(xiàn)大約80%的品種缺少這些有益的基因塊，這表明有很大的改進(jìn)空間。確切地知道哪些基因參與其中意味著可以很快完成這些改進(jìn)的育種過程。不用等植物生長和成熟，你可以在植物發(fā)芽后不久檢查它的基因，如果你不想要的話，就把它扔掉。

第七段：

Upgrades suitably developed, the question will be how to get them into the wider world.?Dr Varshney says that big agricultural and seed companies tend to have limited interest in chickpeas.That means more reliance on smaller firms and co-operatives for distribution.?If this can be done, though, the humble chickpea will join the big boys like rice and soyabeans as crops whose genes have been analysed for the betterment of human nutrition.

如果育種過程完成升級(jí)，那么問題將是--如何讓它們進(jìn)入更廣闊的世界。瓦爾什尼博士說，大型農(nóng)業(yè)和種子公司對鷹嘴豆的興趣往往有限。這意味著更多地依靠小公司和合作社進(jìn)行分銷。不過，如果能做到這一點(diǎn)，級(jí)別低下的鷹嘴豆將加入大米和大豆等大的農(nóng)作物行列。這些經(jīng)過基因分析的農(nóng)作物，可以改善人類營養(yǎng)。