2015 – WHAT WENT WRONG? WHY WERE MOST YIELDS SO LOW? DR. LOWELL ZELINSKI PRECISION AG CONSULTING

WHAT WENT RIGHT IN 2015? MUCH SHORTER PRESENTATION ALMOST NOTHING NO FROST AFTER BUD BREAK OK – THAT’S IT

HOW BAD WAS IT? WAS BAD FOR ALMOST EVERYONE A VERY FEW DID OK SO PROBABLY NOTHING AN INDIVIDUAL GROWER DID MOST YIELDS OFF BY 50% OR MORE SOME AS LOW AS 100% – NOT WORTH HARVESTING INSURANCE WROTE OFF ONE BLOCK IN LATE AUGUST – 100% LOSS – NO NEED TO HARVEST MANY BLOCKS THAT USUALLY GIVE 20 TONS, GAVE 2 TONS I HAVE ABOUT 40 HARVESTS THIS YEAR – EVERY ONE IS DEPRESSING

WHICH VARIETIES ? DIDN’T SEEM TO REALLY MATTER SYRAH AND CABERNET SAUVIGNON MAY BE THE WORST DON’T KNOW HOW BAD CABERNET SAUVIGNON IS YET SYRAH IS MOSTLY DEVASTATED ZINFANDEL, PETITE SIRAH (DURIF), GRENACHE, AND MOURVEDRE MAYBE NOT AS BAD BUT STILL NOT GOOD

THE BIG QUESTION IS "WHY?"

MANY POSSIBLE REASONS SALT ACCUMULATION IN ROOT ZONE – LACK OF RAIN FOR FOUR YEARS PRIMARY BUD NECROSIS – POOR FLOWERING CONDITIONS IN THE SPRING OF 2014 TRUNK AND CORDON DISEASES 3 INCHES OF RAIN IN JULY – BUNCH ROT HAIL IN MID-JUNE (REALLY?) WRONG TRELLIS SYSTEM

REASONS THESE ALL MAY HAVE PLAYED A ROLE BUT NOT FOR EVERYONE IF IT WERE DUE TO THESE CONDITIONS, THERE WOULD BE GOOD YIELDS OUT THERE SOMEWHERE

GRAPEVINE ANATOMY REVIEW

TWO YEAR PROCESS TAKES 2 YEARS TO DEVELOP CLUSTERS – AND BERRIES – AND YIELD YEAR 1 – COMPOUND BUDS FORM – BUT DO NOT GROW IN AXIALS IN NODES CONTAIN CLUSTERS, TENDRILS AND ABOUT 10 NODES OF NEXT YEARS’ GROWTH YEAR 2 – PRIMARY BUD (USUALLY) STARTS TO GROW GETS ENERGY AND NUTRIENTS FROM TRUNK AND CORDONS AT START THE FLOWERS FORM AND GO THROUGH POLLINATION AND FERTILIZATION (NOT THE SAME)

BUDS PRIMARY BUD NECROSIS

FLOWERING IN GRAPES Grape flowers are hermaphroditic Both male and female parts Usually self-pollinated That is why flowers are not “showy”

DIFFERENCE BETWEEN POLLINATION AND FERTILIZATION POLLINATION IS THE DEPOSITION OF POLLEN ON THE STIGMA FERTILIZATION IS THE JOINING OF THE MALE AND FEMALE HAPLOID GAMETES IN THE OVULE THERE ARE 4 FEMALE EGGS IN A GRAPE OVULE MAXIMUM NUMBER OF SEED PER BERRY IS 4 THE MORE SEEDS, THE BIGGER THE BERRY

THE CAP FIVE FLOWER PETALS FUSED TOGETHER UNLIKE MOST FLOWERS – IT OPENS AT THE BASE FIRST – NOT THE TOP THE FORMATION OF THE INDIVIDUAL PETALS IS CAUSED BY THE FORMATION OF AN ABSCISSION LAYER BETWEEN THEM ABSCISSION LAYER FORMATION IS A GROWTH PROCESS IF THE CELLS IN THE LAYER RUN OUT OF ENERGY, THEY DON’T COMPLETE THE OPENING AND THE CAP GETS STUCK

INCOMPLETE ABSCISSION LAYER DEVELOPMENT

EFFECTS OF CAP RETENTION ANTHERS DO NOT EXTEND TO A POSITION ABOVE THE STIGMA THE HUMIDITY IS TOO HIGH UNDER THE CAP TO ALLOW FOR “RAPID” DEHISCENCE (DRYING OF THE ANTHER SACK) AND RELEASE OF POLLEN POLLINATION IS GREATLY REDUCED THUS, FERTILIZATION IS GREATLY REDUCED THIS IS ONE REASON FOR POOR FRUIT SET IN 2015!!!

THE POLLEN TUBE THE MALE GAMETE (SPERM) NEEDS TO MAKE IT DOWN THROUGH THE STIGMA/STYLE/OVULE INTO THE BOTTOM END OF THE POTENTIAL SEED AND JOIN WITH THE EGG FOR FERTILIZATION TO OCCUR THE DEVELOPMENT OF THE POLLEN TUBE IS A “GROWTH” PROCESS IT REQUIRES ENERGY FOR ORGANELLES AND CELLULAR MEMBRANE FORMATION IT IS NOT LIKE A BALLOON EXPANDING

Generalized Diagrammatic Representation of a Pollen Tube.Features and components generally considered to be present at the growing tip of pollen tubes. Vernonica E. Franklin-Tong Plant Cell 1999;11: ©1999 by American Society of Plant Biologists

POLLEN TUBE DEVELOPMENT EACH OF THESE ORGANELLES AND CELLULAR MEMBRANES REQUIRE THE “ALLOCATION” OF RESOURCES AND ENERGY AS THESE NEEDED STRUCTURES ARE BEING FORMED – ENERGY – CONTAINED IN THE POLLEN GRAIN – IS BEING EXPENDED

ACTUAL POLLEN TUBE DEVELOPMENT THIS IMAGE SHOWS ACTUAL POLLEN TUBE DEVELOPMENT NOT LIKE THE DRAWING

POLLEN TUBE GROWTH AND FERTILIZATION THE RATE OF POLLEN TUBE GROWTH DEPENDS ON TEMPERATURE IF IT IS TOO COLD – LESS THAN ABOUT 80 DEGREES – GROWTH IS SLOWED SO – WAS 2015 BLOOM TIME WEATHER FAVORABLE FOR FERTILIZATION? IF HOT AND DRY – STIGMA WILL DRY OUT AND NOT INDUCE POLLEN TUBE DEVELOPMENT IF WET (HIGH HUMIDITY) – POLLEN WILL ABSORB TOO MUCH WATER AND “EXPLODE” BEFORE REACHING STIGMA IF COOL – POLLEN GRAINS MAY RUN OUT OF ENERGY BEFORE POLLEN TUBE CAN MAKE IT TO THE EGG SO HOW WAS 2015 BLOOM TIME WEATHER?

NEXT, LETS REVIEW 2014 BLOOM-TIME WEATHER CAN WE RULE OUT FLOWER DEVELOPMENT ISSUES IN 2014? (PRIMARY BUD NECROSIS)

BLOOM TIME WEATHER 2014 GREEN = FAVORABLE RED = NOT FAVORABLE

SO WHAT ABOUT 2015? TEMPERATURE NEEDED TO BE AROUND OR ABOVE 80 FOR GOOD POLLEN TUBE GROWTH FOR INDIVIDUAL GRAPE FLOWERS AND POLLEN, THEY ARE ONLY “RECEPTIVE” FOR ABOUT 2 DAYS – AFTER THAT THEY ARE INFERTILE NOT ALL FLOWERS ON A CLUSTER “BLOOM” AT THE SAME TIME IT’S USUALLY A 1-2 WEEK PROCESS THIS YEAR – A 3 TO 4 WEEK (OR LONGER) PROCESS SEE NEXT SLIDE

BLOOM TIME WEATHER 2015 GREEN = FAVORABLE RED = NOT FAVORABLE

2015 BLOOM TIME WEATHER MOST OF MAY (BLOOM) WAS VERY UNFAVORABLE TO FERTILIZATION BLOOM SEEMED TO LAST FOREVER – SO EVEN IF THERE WERE “FAVORABLE” DAYS, IT WASN’T FAVORABLE FOR VERY MANY BERRIES PER CLUSTER POLLEN TUBE GROWTH (CONTROLLED BY TEMPERATURE) WAS INHIBITED TO SUCH AN EXTENT THAT FERTILIZATION WAS GREATLY REDUCED MANY BERRIES THAT ACTUALLY HAD A POLLINATED SEED – ONLY HAD ONE FLOWER CAP RETENTION – JUST MADE IT WORSE THIS IS A WINE COMMUNITY PROBLEM. WINERIES NEED TO HELP GROWERS OUT THIS YEAR (IF THEY CAN) OR THERE WON’T BE GROWERS IN THE FUTURE!