The C4 crop maize (Zea mays) is the most widely grown cereal crop worldwide and is an essential feedstock for food and bioenergy. Improving maize yield is important to achieve food security and agricultural sustainability in the 21st century. One potential means to improve crop productivity is to enhance photosynthesis. ictB, a membrane protein that is highly conserved across cyanobacteria, has been shown to improve photosynthesis, and often biomass, when introduced into diverse C3 plant species. Here, ictB from Synechococcus sp. strain PCC 7942 was inserted into maize using Agrobacterium-mediated transformation. In three controlled-environment experiments, ictB insertion increased leaf starch and sucrose content by up to 25% relative to controls. Experimental field trials in four growing seasons, spanning the Midwestern United States (Summers 2018 & 2019) and Argentina (Winter 2018 & 2019), showed an average of 3.49% grain yield improvement, by as much as 5.4% in a given season and up to 9.4% at certain trial locations. A subset of field trial locations was used to test for modification of ear traits and ФPSII, a proxy for photosynthesis. Results suggested that yield gain in transgenics could be associated with increased ФPSII, and the production of longer, thinner ears with more kernels. ictB localized primarily to the microsome fraction of leaf bundle-sheath cells, but not to chloroplasts. Extramembrane domains of ictB interacted in vitro with proteins involved in photosynthesis and carbohydrate metabolism. To our knowledge, this is the first published evidence of ictB insertion into a species using C4 photosynthesis and the largest-scale demonstration of grain yield enhancement from ictB insertion in planta. Results show that ictB is a valuable yield gene in the economically important crop maize, and are an important proof of concept that transgenic manipulation of photosynthesis can be used to create economically viable crop improvement traits.

The relative importance of the different sources of canker varies from year to year. Some, e.g., pruning wounds and injuries from verticilliosis, become less, while others, such as dead twigs and fruit pedicels, become more significant with time. Still others show no definite trends but fluctuate according to conditions.Leaf scars are vulnerable for a time after leaf fall, because of a temporary absence of wound periderm in the leaf base, but the development of cankers from leaf scar infection is determined by an infrequent coincidence of physiological and meteorological factors.Some insects such as the oriental fruit moth (Laspeyresia molesta Busck.), the shot-hole borer (Scolytus rugulosus Ratz.), and the peach borer (Synanthedon exitiosa Say.) can cause injuries which frequently become cankered afterwards. The lesser peach borer (Synanthedon pictipes G. & R.) is seldom a primary parasite but may stimulate necrotic processes through its destruction of callus in cankers. The peach is most susceptible to canker in the fall, and injuries such as pruning cuts made at that time are much more subject to infection than those made at any other time of the year. The incidence of peach canker and of winter injury can also be increased significantly by prolonging the period of open cultivation. At least three types of winter injury have been observed, all of which may give rise to serious cankers.From 75 to 85% of the open cankers of all ages overwintering on the tree remain active. There is also a tendency for cankers to become less active with increasing age. Surgical treatment of important cases is of considerable value.

Whereas Cryplosporclln viticola (Reclclicli) Shear (PIzott~opsis ailicoln Sacc.) has Ion? been reco?nizetl as the causal agent of the clead-arm disease of grapes, pyrnidia of Physalosporn ohlirsa (Schw.) Cke. (Splincropsis ?11nlor?lwz Pecli.) have also been found in lesions on trunks, canes, and tendrils. Both funqi \\rere isolated in about equal proportions, either alone or together, from lesions on trunks ancl st~111s. On the other hanci, 1'. oiticoln, but not S . ~inlnrrc?rz. \\;as isolatecl fro111 a few lesions on current season shoots and the foliage. 130th fungi were capable of infecting freshly cut stubs artificially inoculated \\~ith spore suspensions and could be re-isolated from the resulting lesions. The significance of S . nzalornvz in the etiology of the dead-arm disensc is a t present uncertain. rnacle by one of us (J.L.T.) while acting assistant to Mr. Chamberlain.

Drainage water recycling (DWR) involves capture, storage, and reuse of surface and subsurface drainage water as irrigation to enhance crop production during critical times of the growing season. Our objectives were to synthesize 53 site-years of data from 1996 to 2017 in the midwestern United States to determine the effect of DWR using primarily subirrigation on corn (Zea mays L.) grain yield and yield variability and to identify precipitation factors at key stages of corn development (V1-V8, V9-VT, R1-R2, R3-R4, and R5-R6) that correlated to an increase in yield with DWR. A generalized additive model was used to quantify and characterize the relationship between precipitation and corn grain yield during corn development stages and to determine if that relationship differed between DWR and free drainage (FD). Corn yield response to precipitation was generally similar between DWR and FD, except during the critical period of V9-R2, in which DWR was more resilient to precipitation extremes than FD. Drainage water recycling was generally more responsive than FD in years with low and normal precipitation (<181 mm). When precipitation was low (27-85 mm) from V9 to R2, DWR had higher yields (77% of the site-years evaluated), with an average yield increase of 3.6 Mg ha −1 (1.2-7.5 Mg ha −1 ). Overall, FD had 28% greater yield variability than DWR. Additional research is needed on DWR impacts on different soils and locations throughout this region to improve the stability of corn yields and to develop automated DWR systems for enhancing efficiency of water management with increasing climate variability.

Two species of Valsa have been isolated more or less consistently from cankers of various ages, and from "die-back" twigs on the peach. In culture, one species, identified as Valsa leucostoma (Pers.) Fr., is hair-brown and has small dark pycnidia exuding cirri when mature. On the host, its stroma is compact in texture, contains no host cells and is delimited beneath by a black zone of carbonized fungal and host cells. Ascospores of V. leucostoma measure 10–17 by 2–4.5 μ. The other species, which has been assigned to V. cincta Fr., is whitish to olive buff in culture and has large light-colored pycnidia containing, though rarely exuding, spores. On the host, the stroma of V. cincta is comparatively loose in texture, contains host cells and is delimited from the cortex of the host by a thin, black zone, sometimes only marginal. Ascospores of V. cincta measure 14–28 by 4–7 μ. In both species, the pycnospores range from 5 to 10 μ in length and 1 to 2 μ in width. These organisms, along with Sclerotinia fructicola (Wint.) Rehm., were used in series of infection experiments at frequent intervals over a period of two years. Similar series of checks were also provided. Periodical observations and measurements furnished detailed case histories of all wounds concerned. V. cincta was found to be a virulent wound-parasite, able not only to infect freshly made wounds during the late autumn, winter and spring, but also to give rise to perennial cankers. Infection with this organism rarely occurred during June, July and August. V. leucostoma proved in these experiments to be almost, if not quite, incapable of initiating cankers on the peach. S. fructicola parasitized the tissues of branches and produced considerable necrosis during the first three weeks after inoculation during the growing season. Subsequently the lesions proceeded to heal. The degree of infection and the amount of resultant necrosis in wounds inoculated with S. fructicola during the dormant season were dependent upon the conditions of temperature and humidity then prevailing. S. fructicola, while capable of inducing lesions on the stem, cannot be regarded as the cause of typical peach canker. Some of the factors influencing infection by the three organisms mentioned above are briefly discussed.