Promoting resilience in rain grown cotton systems with plant growth regulators

Abstract

Rain grown cotton production is typified by significant climate variability with water limitation a focal constraint. Ensuing system exposure to climate risk results in substantial variability in production area, lint yield, lint quality and profit outcomes. Climate risk management involves manipulating multiple agronomic management and genetic solutions simultaneously; moderating existing limitations to reach the system water-limited yield potential. Such strategies can introduce management diversity to the farming system, but lack application agility, have added implementation costs and system rain-dependency often precludes their implementation. This thesis informs discourse regarding novel adaptive management opportunities utilising plant growth regulators (PGRs), to enable in-season responsive management of limitations under dynamic climatic conditions, offset climate variability and improve system resilience. Ensuing outcomes being increased farm-gate profits, through provision of improved crop resource use efficiencies, lint yield and quality outcomes, with less annualised variability. A scarcity of detailed information exists regarding cotton crop and plant responses to exogenous Gibberellin, Cytokinin and Gibberellin biosynthesis inhibiting PGR treatment scenarios, notably in early growth and under water-limited rain grown production contexts. Understanding these responses can enable future development of frameworks for strategic, predictive applications within rain grown cotton systems.