Main Oscar, Jacquemot Marie-Pierre, Griveau Yves, Guillaume Sophie, Demonceaux Claire, Lopez-Marnet Paul-Louis, Rey Sébastien, Fargier Sébastien, Sartre Pascal, Montagnier Christophe, Uijttewaal Anthony, Mangel Nathalie, Meunier Florence, Reymond Matthieu, Méchin Valérie, Coursol Sylvie
Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), Versailles, France.
Unité Expérimentale DiaScope, INRAE, Mauguio, France.
Front Plant Sci. 2023 Mar 14;14:1142462. doi: 10.3389/fpls.2023.1142462. eCollection 2023.
With dwindling global freshwater supplies and increasing water stress, agriculture is coming under increasing pressure to reduce water use. Plant breeding requires high analytical capabilities. For this reason, near-infrared spectroscopy (NIRS) has been used to develop prediction equations for whole-plant samples, particularly for predicting dry matter digestibility, which has a major impact on the energy value of forage maize hybrids and is required for inclusion in the official French catalogue. Although the historical NIRS equations have long been used routinely in seed company breeding programmes, they do not predict all variables with the same accuracy. In addition, little is known about how accurate their predictions are under different water stress-environments.
Here, we examined the effects of water stress and stress intensity on agronomic, biochemical, and NIRS predictive values in a set of 13 modern S0-S1 forage maize hybrids under four different environmental conditions resulting from the combination of a northern and southern location and two monitored water stress levels in the south.
First, we compared the reliability of NIRS predictions for basic forage quality traits obtained using the historical NIRS predictive equations and the new equations we recently developed. We found that NIRS predicted values were affected to varying degrees by environmental conditions. We also showed that forage yield gradually decreased as a function of water stress, whereas both dry matter and cell wall digestibilities increased regardless of the intensity of water stress, with variability among the tested varieties decreasing under the most stressed conditions.
By combining forage yield and dry matter digestibility, we were able to quantify digestible yield and identify varieties with different strategies for coping with water stress, raising the exciting possibility that important potential selection targets still exist. Finally, from a farmer's perspective, we were able to show that late silage harvest has no effect on dry matter digestibility and that moderate water stress does not necessarily result in a loss of digestible yield.
随着全球淡水资源供应减少以及水资源压力增大，农业在减少用水方面面临着越来越大的压力。植物育种需要高分析能力。因此，近红外光谱法（NIRS）已被用于为全株样本建立预测方程，特别是用于预测干物质消化率，这对饲用玉米杂交种的能量价值有重大影响，并且是法国官方目录收录所必需的。尽管历史悠久的NIRS方程长期以来一直在种子公司的育种计划中常规使用，但它们对所有变量的预测准确性并不相同。此外，对于它们在不同水分胁迫环境下的预测准确性知之甚少。
在此，我们研究了水分胁迫和胁迫强度对13个现代S0 - S1饲用玉米杂交种在四种不同环境条件下的农艺、生化和NIRS预测值的影响，这四种环境条件是由北部和南部地点的组合以及南部两个监测到的水分胁迫水平产生的。
首先，我们比较了使用历史NIRS预测方程和我们最近开发的新方程获得的基本饲草质量性状的NIRS预测可靠性。我们发现NIRS预测值受到环境条件的不同程度影响。我们还表明，饲草产量随着水分胁迫而逐渐降低，而干物质和细胞壁消化率无论水分胁迫强度如何都有所增加，在胁迫最严重的条件下，测试品种之间的变异性降低。
通过结合饲草产量和干物质消化率，我们能够量化可消化产量并识别具有不同应对水分胁迫策略的品种，这增加了仍然存在重要潜在选择目标的令人兴奋的可能性。最后，从农民的角度来看，我们能够表明晚青贮收获对干物质消化率没有影响，并且适度的水分胁迫不一定会导致可消化产量的损失。
