After domestication from lowland teosinte parviglumis (Zea mays ssp. parviglumis) in the warm Mexican southwest, maize (Zea mays ssp. mays) colonized the highlands of Mexico and South America. In the highlands, maize was exposed to lower temperatures that imposed strong selection on flowering time. Phospholipids are important metabolites in plant responses to low-temperature, low phosphorus availability and have also been suggested to influence flowering time. Here, we combined linkage mapping analysis with genome scans to identify High PhosphatidylCholine 1 (HPC1), a gene which encodes a phospholipase A1 enzyme, as a major driver of phospholipid variation in highland maize. Common garden experiments demonstrated strong genotype-by-environment interactions associated with variation at HPC1, with the highland HPC1 allele leading to higher fitness in highlands, possibly by hastening flowering. The HPC1 variant we identified in highland maize results in impaired function of the encoded protein due to a polymorphism in a highly conserved sequence. A meta-analysis indicated a strong association between the identity of the amino acid at this position and optimal growth in prokaryotes. Mutagenesis of HPC1 via genome editing validated its role in regulating phospholipid metabolism. Finally, we show that the highland HPC1 allele entered cultivated maize by introgression from the wild highland teosinte Zea mays ssp. mexicana and has been maintained in maize breeding lines from Northern US, Canada and Europe. Thus, HPC1 introgressed from teosinte mexicana underlies a large metabolic QTL that modulates phosphatidylcholine levels and has an adaptive effect at least in part via induction of early flowering time.

Three polymorphisms were identified in a 1.6-kb fragment of the porcine calpastatin (CAST) gene and these polymorphisms were used for genetic linkage mapping. Linkage analysis revealed significant linkage of CAST to five microsatellites previously mapped to porcine chromosome 2; these microsatellites were S0010, S0226, SWI4, Sw395 and Sw776. A somatic cell hybrid panel was used to determine the chromosomal localization of CAST and the microsatellites S0091, S0226 and Sw395. All of these were localized to the region 2q2.1-q2.4.

Corn planting and harvest scheduling is an important problem due to having a significant impact on corn yield, balancing the capacities for harvest, transport, and storage operations. Different corn hybrids also have different planting window and poor planting and harvest schedules may cause erratic weekly harvest quantities and logistical and productivity issues. In the 2021 Syngenta Crop Challenge, Syngenta released several large datasets that recorded the historical daily growing degree units (GDU) of two sites and provided planting window, required GDUs, and harvest quantity of corn hybrids planted in these two sites. Then, participants of this challenge were asked to schedule planting and harvesting dates of corn hybrids under two storage capacity scenarios so that facilities are not over capacity in harvesting weeks and have consistent weekly harvest quantities. The two storage capacity scenarios include: (1) planting and harvest scheduling given the maximum storage capacity, and (2) planting and harvest scheduling without maximum storage capacity to determine the lowest possible capacity for each site. In this paper, we propose two mixed integer linear programming (MILP) models for solving this problem considering both the storage capacity and the uncertainty in GDUs. Our results indicate that our proposed models can provide optimal planting and harvest scheduling under different GDU possibilities which ensures consistent weekly harvest quantities that are below the maximum capacity.

SummaryThe porcine retinoic acid receptor‐γ gene (RARG) has been mapped by restriction fragment length polymorphism analysis to porcine chromosome 5. The placement of RARG distal to the diacylglycerol kinase gene increases the length Of the existing map (PiGMaP) and adds a fifth type‐I marker to this sparsely mapped chromosome. This augments the homology of pig chromosome 5 and human chromosome 12 established by previous comparative mapping.