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VARIATION IN HEADING DATES OF PERENNIAL RYEGRASS CULTIVARS AS INFLUENCED BY SPRING AND EARLY SUMMER TEMPERATURES
Author(s) -
Camlin M. S.
Publication year - 1975
Publication title -
grass and forage science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.716
H-Index - 56
eISSN - 1365-2494
pISSN - 0142-5242
DOI - 10.1111/j.1365-2494.1975.tb01391.x
Subject(s) - cultivar , perennial plant , spring (device) , heading (navigation) , agronomy , biology , geography , environmental science , mechanical engineering , geodesy , engineering
Ear emergence data for 9 cultivars of perennial ryegrass have been recorded in Northern Ireland at the Plant Testing Station, Crossnacreevy, each year since 1967. These data show that while early spring (March‐April) temperatures have a marked effect on the heading of early cultivars such as Gremie and Aberystwyth S24, the behaviour of later cultivars is more directly affected by temperatures at the time of their stem internode elongation. Ear emergence dates of late cultivars bear no fixed relationship to those of early cultivars. It is concluded that while records of early spring temperatures can be used to predict, with reasonable accuracy, the heading dates of early cultivars, such records do not provide a reliable basis for the prediction of heading dates of later cultivars. In Northern Ireland, reliable prediction of cutting dates for later cultivars to obtain herbage of a required level of digestibility is only possible on a short‐term (one‐two week) basis. Such predictions must take account of growing conditions in each individual year.