Badu-Apraku B, Talabi A O, Ifie B E, Chabi Y C, Obeng-Antwi K, Haruna A, Asiedu R
International Institute of Tropical Agriculture, Ibadan, Nigeria.
West Africa Centre for Crop Improvement, Univ. of Ghana, Accra.
Crop Sci. 2018 Nov-Dec;58(6):2399-2412. doi: 10.2135/cropsci2018.03.0168. Epub 2018 Aug 30.
Drought is a key maize ( L.) production constraint in sub-Saharan Africa. Fourteen, fifteen, and twenty-five extra-early maturing maize cultivars, with varying resistance and drought and low soil N tolerance, were developed from 1995 to 2000 (Period 1), 2001 to 2006 (Period 2), and 2007 to 2012 (Period 3), respectively. The objectives of this study were to examine yield gains in the cultivars and to investigate inter-trait relationships and yield stability under six drought and 17 rainfed conditions in West Africa from 2013 to 2016. Annual rate of yield increase across cultivars was 0.034 (3.28%) and 0.068 Mg ha (2.25%), whereas yield gains per period were 0.17 and 0.38 Mg ha under drought and rainfed environments, respectively. Yield gains under drought and rainfed environments were related to prolonged flowering period, increased plant and ear heights, improved stalk lodging, and ear and plant aspects, whereas delayed leaf senescence and increased number of ears per plant accompanied yield improvement under drought only. Ear aspect and number of ears per plant were primary contributors to yield and could be used as selection criteria for yield enhancement under drought and rainfed conditions. High-yielding and stable cultivars across all environments based on additive main effects and multiplicative interaction (AMMI) biplot included '2004 TZEE-Y Pop STR C' and 'TZEE-W Pop STR BC C' of Period 2 and '2009 TZEE-W STR', 'TZEE-Y STR 106', 'TZEE-W STR 107', and 'TZEE-W DT C STR C' of Period 3. These cultivars could be commercialized to improve food self-sufficiency in sub-Saharan Africa.
干旱是撒哈拉以南非洲地区玉米（L.）生产的关键制约因素。1995年至2000年（第1阶段）、2001年至2006年（第2阶段）和2007年至2012年（第3阶段）分别培育出了14个、15个和25个超早熟玉米品种，这些品种具有不同的抗性以及耐旱和耐低土壤氮能力。本研究的目的是考察这些品种的产量增益情况，并调查2013年至2016年在西非六种干旱条件和17种雨养条件下性状间的关系以及产量稳定性。各品种的年增产率为0.034（3.28%）和0.068 Mg/ha（2.25%），而在干旱和雨养环境下，每个阶段的产量增益分别为0.17 Mg/ha和0.38 Mg/ha。干旱和雨养环境下的产量增益与花期延长、株高和穗位高增加、茎倒伏情况改善以及果穗和植株外观有关，而仅在干旱条件下，叶片衰老延迟和单株果穗数增加伴随着产量提高。果穗外观和单株果穗数是产量的主要贡献因素，可作为干旱和雨养条件下提高产量的选择标准。基于加性主效应和乘积互作（AMMI）双标图，在所有环境下高产且稳定的品种包括第2阶段的“2004 TZEE - Y Pop STR C”和“TZEE - W Pop STR BC C”以及第3阶段的“2009 TZEE - W STR”、“TZEE - Y STR 106”、“TZEE - W STR 107”和“TZEE - W DT C STR C”。这些品种可以商业化，以提高撒哈拉以南非洲地区的粮食自给自足水平。
