Intensive systems with two or three rice (Oryza sativa L.) crops per year account for about 50% of the harvested area for irrigated rice in Asia. Any reduction in productivity or sustainability of these systems has serious implications for global food security. Rice yield trends in the world’s longest-running long-term continuous cropping experiment (LTCCE) were evaluated to investigate consequences of intensive cropping and to draw lessons for sustaining production in Asia. Annual production was sustained at a steady level over the 50-y period in the LTCCE through continuous adjustment of management practices and regular cultivar replacement. Within each of the three annual cropping seasons (dry, early wet, and late wet), yield decline was observed during the first phase, from 1968 to 1990. Agronomic improvements in 1991 to 1995 helped to reverse this yield decline, but yield increases did not continue thereafter from 1996 to 2017. Regular genetic and agronomic improvements were sufficient to maintain yields at steady levels in dry and early wet seasons despite a reduction in the yield potential due to changing climate. Yield declines resumed in the late wet season. Slower growth in genetic gain after the first 20 y was associated with slower breeding cycle advancement as indicated by pedigree depth. Our findings demonstrate that through adjustment of management practices and regular cultivar replacement, it is possible to sustain a high level of annual production in irrigated systems under a changing climate. However, the system was unable to achieve further increases in yield required to keep pace with the growing global rice demand.

Modern cotton (Gossypium hirsutum L.) cultivars are more productive and have unique growth and fruiting characteristics due to optimization of genetics and management practices in the past 30 yr. The most recent work evaluating nutrient uptake and partitioning by cotton was conducted in the early 1990s, necessitating a re-evaluation of nutrient accumulation and requirements in modern high productivity cultivars. Modern cultivar (FiberMax [FM] 958 and Deltapine [DP] 1646) resource allocation, including dry matter production, yields, and accumulation and partitioning of N, P, K, Ca, Mg, and S to different organs, was compared with that of a 1990s cultivar (Paymaster [PM] HS26) in 2018 and 2019. The modern cultivars tested in this study partitioned a greater percentage of dry matter, N, P, K, and S into the fruit than the older cultivar, highlighting the importance of partitioning for increased production potential of these cultivars from the 1990s to the 2010s. Greater efficiencies in partitioning and remobilization of N, P, K, and S resulted in 66, 88, 64, and 30% increase in the amount of lint yield produced for every unit of uptake, respectively, under favorable growing conditions. These findings suggest that existing fertility paradigm in cotton may underestimate the accumulation expectations during the middle and latter part of the growing season. These results can be a basis for optimizing nutrient application to address partitioning changes. Adjusting nutrient recommendations to the shift in cultivar growth characteristics may improve both yield and application efficiency of fertilizers. 1 INTRODUCTION Nutrient uptake and partitioning among plant tissues of cotton (Gossypium hirsutum L.) grown under both dryland and irrigated conditions have been documented in

Recent technological advances in cotton (Gossypium hirsutum L.) phenotyping have offered tools to improve the efficiency of data collection and analysis. High-throughput phenotyping (HTP) is a non-destructive and rapid approach of monitoring and measuring multiple phenotypic traits related to the growth, yield, and adaptation to biotic or abiotic stress. Researchers have conducted extensive experiments on HTP and developed techniques including spectral, fluorescence, thermal, and three-dimensional imaging to measure the morphological, physiological, and pathological resistance traits of cotton. In addition, ground-based and aerial-based platforms were also developed to aid in the implementation of these HTP systems. This review paper highlights the techniques and recent developments for HTP in cotton, reviews the potential applications according to morphological and physiological traits of cotton, and compares the advantages and limitations of these HTP systems when used in cotton cropping systems. Overall, the use of HTP has generated many opportunities to accurately and efficiently measure and analyze diverse traits of cotton. However, because of its relative novelty, HTP has some limitations that constrains the ability to take full advantage of what it can offer. These challenges need to be addressed to increase the accuracy and utility of HTP, which can be done by integrating analytical techniques for big data and continuous advances in imaging.

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