A major source of green fodder and silage for ruminant livestock in South Asia, maize (Zea mays L.) is a staple for livestock with chronic feed shortages, reduction in area of cultivation and rising climatic volatility limiting livestock productivity in the region. Single-cross hybrids that are selected for high yields in uniform high input systems are less suited for forage production because of high seed costs, uniformity, susceptibility to heat and drought stress, and selection criteria which are not based on vegetative yield and stover quality. The goal of this review is to synthesize what is known about the genetic makeup of multi-parent and double cross maize hybrids for forage and their buffering capacity. It examines the gene action (additive and non-additive) and general and specific combining ability of green fodder production, dry matter production, crude protein, fibre fractions (NDF, ADF and ADL) and invitro digestibility in relation to the utilization of the heterotic group. It also discusses the topics of population buffering, developmental homeostasis, genotype-by-environment interactions and stability analysis, as well as a few other miscellaneous topics. The biomass digestibility trade-off is discussed and explained by using a multivariate selection index (MGIDI and MTSI). Lastly, the use of marker-assisted selection, MAGIC and NAM populations, and genomic selection in combination with multi-parent breeding pipelines is discussed. These strategies can provide a feasible pathway towards creating dual purpose maize varieties that produce both grain and fodder, while simultaneously being able to withstand climate change, in South Asia.
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