From 2021 to 2023, the effects of trellis type (two-wire “T” versus high single wire), rootstock (own-rooted, Freedom, or 1103P), and annual nitrogen fertilizer application rate (40 versus 80 lbs N/acre) were evaluated in the San Joaquin Valley to determine impacts on Sunpreme productivity, raisin quality and mineral nutrition. The T-trellis increased yield approximately 10%, with a slight decrease in raisin quality, compared to the high single-wire trellis. Rootstocks also increased yield by 10%. The higher N rate did not increase raisin yield, but it reduced raisin quality. None of the treatments tested affected preharvest fruit drop. Petiole and blade nutrient concentrations were affected to some extent by all treatments, but most nutrients, other than potassium (K) and zinc (Zn), were present at concentrations that are generally considered adequate. Vine nutrition was particularly affected by rootstock, with vines on Freedom having the highest levels of boron (B), potassium (K), and nitrogen (TN), and the lowest Zn Vines on 1103P had the lowest K and highest magnesium (Mg). Own-rooted vines had the lowest NO3-N, Ca, and Mg, but the highest Zn. Effects of rootstocks on nutrition could have management implications, depending on soil type. The amount of select nutrients in 1 t of raisins was determined. There were approximately 0.0089 kg B, 7.3 kg K, 0.345 kg Mg, 5.8 kg N, and 0.0025 kg Zn in a t of raisins. The quantity of certain nutrients in raisins was most affected by rootstock. Vines on Freedom had the most B and K, and among the most Mg and N. Increasing the N application rate modestly increased yield, and the harvested raisins contained approximately 44.8 to 58.3 kg N/ha, depending on N rate. These values provide practical estimates for nutrient replacement in NDOV vineyards. Overall, yield improvements were achieved with two-wire trellis and rootstocks, while higher N rates increased yield at the expense of quality. Annual applications of 44.8 – 56 kg N per hectare appear sufficient to sustain yield and maintain raisin quality.

Satellite-based evapotranspiration (ET) products such as OpenET are increasingly used for irrigation management and agricultural water accounting, yet…

UC ANR is pleased to announce and congratulate 17 recipients of the 2026 Distinguished Service Awards.

Nature Climate Change - Southern California is rarely affected by tropical cyclones at present. Here the authors show that this could change with warming, leading to an increase in landslide risk...

Larry Bettiga, UCCE viticulture advisor for Monterey, San Benito and Santa Cruz counties, is set to retire July 1. He shaped the wine industry across California and beyond.

A potentially strong El Niño weather pattern will likely emerge this summer and persist through the rest of the year. The hottest years on record generally occur in years when El Niño is active.

Press Release - UC Davis researcher honored for advancing modern fermentation science and winery practice

Francis Eisen's first raisin crop came by accident, after a heat wave left his Muscat grapes dried on the vine in 1877.

Fresno County has ripped out more than 6,000 acres of wine grapes as part of a trend to reduce the crop’s acreage across California.

Exciting opportunity in Davis, CA for University of California Davis Health System as a Assistant...

Where Ojai Vineyard winemaker Adam Tolmach once grew grapes with household names, he planted hybrid varieties no consumer had ever heard of. Now he's making pioneering new wines.

Synopsis. Social media has become widely used by the scientific community for a variety of professional uses, including networking and public outreach. For

Analysis of the grapevine pan-mitochondrial genome reveals extensive structural variation, and shows that nuclear-mitochondrial segments promote cytonuclear interaction during grapevine domestication...

Table grapes have high production costs partly due to laborious picking and packing practices. Mechanized harvest is not yet feasible for whole table grape clusters, but it might be suitable for “fresh cut” (destemmed) table grapes if mechanical damage could be minimized. Preharvest application of methyl jasmonate (MeJA) and 1-aminocyclopropane-1-caboxylic acid (ACC) activate the abscission zone of some grape varieties, improving harvestability and reducing harvest wounds, but effects on postharvest quality of destemmed berries are unknown. Sheegene-12 and Autumn King table grapes treated with 3 mM MeJA and 500 to 750 ppm ACC were destemmed and berry condition evaluated at harvest, and after two and four weeks of postharvest storage. Treatments improved harvestability and reduced destemming wounds of both varieties and generally improved the quality of Sheegene-12 berries at harvest, and after postharvest storage. However, treated Autumn King berries became darker, and more yellow-colored in storage, which is undesirable.

Early September lightning outbreak brings many wildfires, with some damage, but lack of NorCal drought prevents worse outcome The month of September started with a bang--or, rather, the near-constant rumble of thunder from thousands of lightning strikes amid an intense thunderstorm outbreak that affected a broad portions of interior central and much of northern California.

A significant proportion of flowers in crop plants fail to produce seeds, particularly under heat and drought stress. This outcome reflects a regulated developmental process of reproductive abortion, shaped by a complex interplay of genetic, hormonal, and environmental factors that limit crop yield. Unlike abscission, reproductive abortion can occur at multiple developmental stages. In this review, we examine how internal and external cues disrupt the development of florets, ovules, embryos, and seeds in major food crops, including cereals, legumes, and brassicas, under both optimal and stress conditions. Drawing from research in arabidopsis and extending to crop systems, we identify conserved and crop-specific mechanisms, highlight critical knowledge gaps, and propose strategies to enhance reproductive resilience and seed set under abiotic stresses.

Grape Day at the Kearney Agricultural Research and Extension Center – a time-honored learning event dating to the late 1960s.

Australian wine industry icon Dr Richard Smart – ‘The Flying Vine Doctor’ – passed away in Victoria on Wednesday after a long battle with cancer. Andrew Caillard MW described him as “a remarkable man…