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BACKGROUND: Protein percentage and kernel weight affect the endosperm hardness of maize grains. However, changes in starch composition could also modify kernel hardness, which is often predicted through milling ratio. The objective of this work was to evaluate the relationship between changes in starch composition and endosperm hardness, and to assess the effects of protein content and kernel weight on that relationship. For this, we used information obtained from three temperate hybrids in multi‐environmental experiments, as well as experiments conducted under controlled conditions designed to modify starch composition. Milling ratio was determined as maize kernel hardness predictor in both experiments and it was correlated with grain weight and grain composition. RESULTS: In both experiments, milling ratio presented a significant Spearman correlation coefficient with amylose/starch ratio. Milling ratio was significantly related to the amylose/starch ratio using a simple fit with datasets from different experiments and hybrids. Increases in amylose/starch ratio were associated with increases in milling ratio. CONCLUSION: Starch composition was related to milling ratio variations among hybrids of different aptitude for dry milling through different environments, regardless of protein content. Thus, increases in the amylose/starch ratio were related to increases in the milling ratio. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Food grade maize dedicated to dry milling is an ingredient used in everyday foods, such as breakfast cereals, snacks, baked goods, and beer. Argentina has developed a supply chain producing high quality food grade hard endosperm maize for national and international dry milling markets. In modern times, European countries uniquely source their imported hard endosperm food grade maize from Argentina. Here we describe some of the challenges and opportunities this centralized supply chain is facing. There is a 10–30% yield gap between regular dent and hard endosperm commercial hybrids, depending on the specific genotype and environment, and we anticipate it will continue increasing. Grain quality vs. yield trade-off is the most important challenge, and to cope with this issue the supply chain is slowly adapting to use food grade hybrids with higher physical field yields but slightly lower grain hardness than traditional ones. However, there is a clear opportunity to genetically manipulate grain hardness thanks to the known role of the specific proteins involved. Another opportunity is crop management optimization at the field level. Minimum advice is given to farmers other than genotype selection, leaving them with limited decision support regarding fertilizer or plant population, two management practices with significant grain quality effects. Opportunities also arise from market development based on the nutritional characteristics of this specialty grain (such as 122% higher β-branch carotenoids, 4% lower glycemic index of cooked flours because of lower starch digestibility, and 37% higher grain Zn than softer dent germplasm), or sustainability aspects of the supply chain. We highlight the capacity to track farmers through the current use of identity preserved (IP) programs detailing where, who, and how the grain was produced or impose any needed farming practice change. All these aspects are relevant for other food chains using maize dry milling products around the globe. • Largest challenge related to yield vs. quality trade-off. • Tailored field management recommendations for food grade maize are needed. • New specific protein knowledge provides the opportunity for genetic manipulations. • Market opportunities exist based on the nutritional characteristics of this specialty grain. • Current IP programs are a strength for sustainable sourcing needs from food companies. [ABSTRACT FROM AUTHOR]

• Early farming sites exhibit cultural ties to the Tucson Basin Early Agricultural Period. • Maize farming north of the Tucson Basin precedes the appearance of BM II sites. • The Four Corners Basketmaker II complex did not develop in situ. • Low yield, flint maize constrained population growth during the BM II period. • Risk mediated settlement patterns characterize pre-Puebloan farming strategies. The origins of maize farming strategies broadly labeled Basketmaker II have long intrigued archaeologists. Early twentieth century researchers excavating sheltered sites in the Four Corners region of the American Southwest found material culture associated with aceramic farmers that included sophisticated textiles as well as elaborate and exotic mortuary offerings in a region sparsely occupied by foragers. Although early researchers speculated that the San Pedro phase of what is now known as the Early Agricultural Period played a significant role in the emergence of Basketmaker II, data bearing on the topic were scarce for decades. Recent, well-documented excavations in the southern Tucson Basin in advance of urban development have strengthened the argument that pulses of influence, likely including population movement, occurred during this period. Here, we explore the relationship between the Late Archaic, Early Agricultural Period and Basketmaker II maize-dependent economies in search of Basketmaker origins. A complex and dynamic picture emerges calling into question both migration and diffusion arguments for the appearance of Four Corners Basketmaker II. [ABSTRACT FROM AUTHOR]