Breeding Table Grapes Including Types Resistant to Powdery Mildew David Ramming Retired – USDA/ARS – 1975-2013 Objectives Fruit Characteristics Vine Characteristics Objectives Fruit Characteristics Large Berry Size Naturally Large Berry Size Objectives Fruit Characteristics Large Berry Size Naturally Seedless Seed / Seed trace Sizes Seedless Seeded 5 7 9 0 Large Berry Size With Small Trace Objectives Fruit Characteristics Large Berry Size Naturally Seedless Firm, Crisp Berries Attractive Color Attractive Red Color Objectives Fruit Characteristics Large Berry Size Naturally Seedless Firm, Crisp Berries Attractive Color Uniform berries, good flavor, storage ability Disease resistance Objectives Fruit Characteristics Large Berry Size Naturally Seedless Firm, Crisp Berries Attractive Color Medium Cluster Looseness, good berry attachment and good rachis Cluster Looseness Tight Medium Loose Objectives Vine Characteristics Good Production On Spurs Production on Quadrilateral Trained Spur Pruned Objectives Vine Characteristics Good Production On Spurs Growth habit to fit trellis Early Bud Break for low chill areas Disease Resistance Objectives – unwanted traits • Berries that crack • Browning on white fruit from leaf rubbing • Astringent off flavors Objectives determined, then: • Collect germplasm – – Available varieties – Public germplasm collections – Private germplasm collections Breeding and Genetics • Breeding is a numbers game – the more seedlings and cross combinations – the higher chance of finding improved varieties • Breeding is a long term project – Many varieties have come from 5 generations of breeding or more Breeding and Genetics • Breeding is a numbers game – the more seedlings and cross combinations – the better chance of winning. • Breeding is a long term project • Play smart – choose the best parents • Hybridize complimentary parents • Knowledge of inheritance of traits Selection Methods • Must be able to evaluate large number of seedlings efficiently and cost effectively. Selection Methods • Observation of traits in the field – Make decisions as quickly as possible • Some traits easy to observe and do not change • Some traits influenced by environment Selection Methods • Observation of traits in the field – Make decisions as quickly as possible – Have impatience, patience Selection Methods • Observation of traits in the field • Laboratory • Greenhouse Selection Methods • Observation of traits in the field • Laboratory – Leaf disks for red flesh determination Selection Methods • Observation of traits in the field • Laboratory – Leaf disks for red flesh determination – Leaf disks for Powdery mildew evaluation Selection Methods • Observation of traits in the field • Laboratory – Leaf disks for Powdery mildew evaluation – Leaf disks for red flesh determination – Molecular markers Collaborative Pierce’s Disease Project • UC Davis – Walker Lab – Elite PD resistant germplasm – Greenhouse evaluation – Molecular markers • USDA/ARS – Parlier – Elite seedless germplasm – Embryo rescue methods 5 generations in 10 years Breeding Methods Grow Tubes in Field V. rup. X (V. arizonica x V. champinii) Source of Resistance Parent A88-89 1.69 g A81-17 8.5 g A88-80 1.66 g 1.69 g F1 1.66 g BC1 – 8.5 g Breeding for Powdery Mildew Resistance No Fungicides Most important fungal disease Major resistance loci in grapevine species that confer resistance to the powdery mildew fungus Erysiphe necator From: Current understanding of grapesvine defense mechanisms against the biotrophic fungus (Erysiphe necator), the causal agent of powdery mildew disease Source of Origin of R-locus Resistance mechanism Chromosome R-gene type References resistance R-loci TIR-NB-LRR gene (MrRUN1) M. rotundifolia North PCD of penetrated cell RUN1 12 functionally confirmed in 32 ‘Thomas’ America (rapid) transgenic susceptible cultivars M. rotundifolia PCD of penetrated cell North RUN2 ‘Magnolia’/ (lower frequency 18 n.d. 35,84 America ‘Trayshed’ compared to RUN1) PCD of penetrated cell (significantly slower V. vinifera Central and lower frequency Maps to a CC-NB-LRR gene REN1 ‘Kishmish 13 34,39,40 Asia than RUN1) – hyphal cluster vatkana’ growth and sporulation restricted V. cinerea North PCD of penetrated cell REN2 14 n.d. 35,85 ‘Illinois 547-1’ America (slower than RUN1) Interspecific North REN3 n.d. 15 n.d. 86 hybrid ‘Regent’ America PCD of penetrated cell (rapid)/callose REN4 V. romanetii China 18 n.d. 37 encasement of haustoriuma M. rotundifolia North Post-penetration but REN5 14 n.d. 36 ‘Regale’ America mechanism not reported PCD of penetrated cell Riaz S, 2015, REN6 V. piasezkii China 9 n.d. (very rapid)b unpublished data Riaz S, 2015, REN7 V. piasezkii China n.d. 19 n.d. unpublished data 1. n.d. – not determined. 2. a Feechan A, 2015, unpublished data. 3. b Dry I, 2015, unpublished data. Leaf disk analysis for Powdery Mildew • Quick and reliable method for determining leaf PM resistance • Results – Depending on genetics, if 50% susceptible, eliminates this many before going to the field Powdery mildew susceptible Powdery mildew resistant Genes from wild grapevine species postulated to be involved in resistance to the powdery mildew fungus Erysiphe necator Gene Description Vitis species Function and phenotype Defense pathway regulator – complements Arabidopsis Enhanced Disease eds1 mutant. Constitutively high expression in V. VaEDS1 V. aestivalis ‘Norton’ Susceptibility ortholog aestivalis resistant genotype and regulated by SA and PM Pathogenesis-related V. pseudoreticulata Antifungal activity. Increases resistance to PM in VpPR10.1 protein 10 ‘Baihe-35-1’ agroinfiltrated grapevine leaves Aldehyde V. pseudoreticulata Activation of SA signaling? Enhanced resistance to PM VpALDH2B4 dehydrogenase ‘Baihe-35-1’ when overexpressed in Arabidopsis Transcriptional activator of defense-related genes. WRKY domain V. pseudoreticulata VpWRKY1 Enhanced resistance to PM when over expressed in Transcription factor ‘Baihe-35-1’ Arabidopsis Transcriptional activator of defense-related genes? C4C4-type RING finger V. pseudoreticulata VpRFP1 Enhanced resistance to PM when over expressed in protein ‘Baihe-35-1’ Arabidopsis E3 ubiquitin ligase Ubiquitination and degradation of a negative Erysiphe necator- V. pseudoreticulata VpEIRP1 transcriptional regulator of defense? Enhanced resistance induced C3HC4 RING ‘Baihe-35-1’ to PM when over expressed in Arabidopsis finger protein From: Current understanding of grapevine defense mechanisms against the biotrophic fungus (Erysiphe necator), the causal agent of powdery mildew disease Leaf Stem Rachis Fruit Increase breeding efficiency Embryo Rescue of Seedless Grapes Benefits of hybridizing seedless x seedless and embryo culture to recover plants Selection Methods • Observation of traits in the field • Laboratory – Leaf disks for Powdery mildew evaluation – Leaf disks for red flesh determination – Controlled studies of fruit – Molecular markers • Greenhouse – Determine plant characteristics • Field testing is necessary What traits are easier to breed? • Traits with high heritability • Consistently identified year to year • Identifying germplasm with trait desired • Use cultural practices to improve expression of traits Field Trials Are Important • Different growing conditions • Additional people observing selections How to choose a variety for your production program • Determine your goals and objectives • Varies depending on climate, soil, economics, and market How to choose a variety for your production program • Good storage • Maturity time • Fruit traits - Large berry, seedless, skin, firm, sugar/acid balance, uniform berries, good color, cluster size and tightness – Flavor and texture often overlooked How to choose a variety for your production program • Good storage • Maturity time • Fruit traits - Large berry, seedless, skin, firm, sugar/acid balance, uniform berries, good color, cluster size and tightness • Vine vigor and productivity • Disease resistance What affects life of a variety? • Its traits • How well it is tested before release • How growers treat the variety • Introduction of a better variety Flame Seedless introduced 1973 objectionable seed trace poor color development special crisp flesh Fantasy Seedless Crimson Seedless Thompson Seedless Number 1 table grape for over 50 years No perfect variety What affects life of a variety? • One deleterious trait – Correcting culturally can be too costly • Only varieties better than existing ones should be released • Low expression of one trait might be offset by another trait – color Vs crisp Proof for embryo being sexual in source not maternal Thomcord Objection to breeding seedless x seedless Inbreeding depression However, a large amount of variability exists in seedless material Autumn King.