CSIRO Agriculture and Food, Perth, WA, Australia.
University of Queensland, Queensland Alliance for Agricultural and Food Innovation, Leslie Research Centre, Toowoomba, QLD, Australia.
J Exp Bot. 2020 Aug 6;71(16):4751-4762. doi: 10.1093/jxb/eraa201.
Using a field to lab approach, mature deep-rooting traits in wheat were correlated to root phenotypes measured on young plants from controlled conditions. Mature deep-rooting root traits of 20 wheat genotypes at maturity were established via coring in three field trials across 2 years. Field traits were correlated to phenotypes expressed by the 20 genotypes after growth in four commonly used lab screens: (i) soil tubes for root emergence, elongation, length, and branching at four ages to 34 days after sowing (DAS); (ii) paper pouches 7 DAS and (iii) agar chambers for primary root (PR) number and angles at 8 DAS; and (iv) soil baskets for PR and nodal root (NR) number and angle at 42 DAS. Correlations between lab and field root traits (r2=0.45-0.73) were highly inconsistent, with many traits uncorrelated and no one lab phenotype correlating similarly across three field experiments. Phenotypes most positively associated with deep field roots were: longest PR and NR axiles from the soil tube screen at 20 DAS; and narrow PR angle and wide NR angle from soil baskets at 42 DAS. Paper and agar PR angles were positively and significantly correlated to each other, but only wide outer PRs in the paper screen correlated positively to shallower field root traits. NR phenotypes in soil baskets were not predicted by PR phenotypes in any screen, suggesting independent developmental controls and value in measuring both root types in lab screens. Strong temporal and edaphic effects on mature root traits, and a lack of understanding of root trait changes during plant development, are major challenges in creating controlled-environment root screens for mature root traits in the field.
利用田间到实验室的方法，将小麦成熟的深根特性与在受控条件下测量的幼苗根系表型相关联。通过在 3 个田间试验中取芯，在 2 年内确定了 20 个小麦基因型在成熟时的成熟深根特性。田间特性与 20 个基因型在 4 个常用实验室筛选中的表型相关：（i）在播种后 34 天（DAS）4 个年龄的土壤管中进行根出芽、伸长、长度和分枝的表型；（ii）7 DAS 的纸袋和（iii）用于在 8 DAS 时测量主根（PR）数量和角度的琼脂室；和（iv）在 42 DAS 时用于 PR 和节根（NR）数量和角度的土壤篮。实验室和田间根系特性之间的相关性（r2=0.45-0.73）高度不一致，许多特性不相关，没有一个实验室表型在 3 个田间试验中具有相似的相关性。与深田间根系最正相关的表型是：土壤管筛选中最长的 PR 和 NR 轴在 20 DAS 时；以及在 42 DAS 时从土壤篮中得出的狭窄的 PR 角度和宽阔的 NR 角度。纸和琼脂 PR 角度呈正相关且显著相关，但仅在纸屏中外侧的 PR 角度与较浅的田间根系特性呈正相关。土壤篮中的 NR 表型不能由任何筛选中的 PR 表型预测，这表明独立的发育控制以及在实验室筛选中测量两种根系类型的价值。成熟根系特性受时间和土壤条件的强烈影响，并且对植物发育过程中根系特性变化的理解不足，这是在田间为成熟根系特性创建受控环境根系筛选的主要挑战。
