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Wheat Growth staging systems




  • Growth staging systems

    A number of staging systems have evolved for describing wheat development. The Zadoks system, which is becoming the most universally accepted, will be described in detail. In addition, the Haun and the Feekes-Large staging systems will be introduced.

    The Zadoks system applies to any small grain and its stages are easy to identify in the field. It is more detailed than other systems and allows for precise staging. The first digit of this two-digit code shown in table 1 refers to the principal stage of development beginning with germination (stage 0) and ending with kernel ripening (stage 9). Use of the second digit between 0 and 9 subdivides each principal growth stage. A second digit value of 5 usually indicates the midpoint of the principal stage. For example, a 75 refers to medium milk stage of kernel development. In seedling growth, principal growth stage 1, the second digit refers to the number of emerged leaves. To be counted, a leaf must be at least 50 percent emerged. A 13, for example, indicates that three leaves are at least 50 percent emerged on the main shoot. Tiller leaves are not counted.

    For the tillering principal stage (stage 2), the second digit indicates the number of emerged tillers present on the plant. Since stages may overlap, it is possible to combine Zadoks indexes to provide a more complete description of a plant’s appearance. For example, a plant with one tiller and three leaves could be described by either or both of the Zadoks stages 13 and 21 (figure 1). As the plant matures, the Zadoks stages describing kernel development are usually used alone. For purposes of herbicide application, the seedling stage (stage 1) identifying the leaf numbers is useful. A complete description of the Zadoks system is available in the reference (5) by Zadoks, Chang, and Konzak cited at the end of this publication.

    The Haun system is concerned mainly with the leaf production stage of development. The length of each emerging leaf is expressed as a fraction of the length of the preceding fully emerged leaf. For example, a 3.2 indicates that three leaves are fully emerged, and a fourth leaf has emerged two-tenths of the length of the third. Although this system can be modified, it is not as useful in the field where decisions are made using development indicators other than leaf numbers. A publication by Bauer et al (2) has described early wheat development in relation to the Haun system.

    The Feekes-Large system has been widely used, but is becoming less popular. It numerically identifies stages such as tillering, jointing, and ripening, but lacks the more detailed attributes of the Zadoks and Haun systems. Table 1 shows stages of the Feekes scale next to the corresponding Zadoks stages.

    Table 1. Condensed summary of the Zadoks two-digit code system for growth staging in wheat with corresponding Feekes scale

     
    Zadoks codeDescriptionCorresponding
    Feekes code
    Principal
    stage
    Secondary
    stage
    0 Germination 
     0Dry kernel 
     1Start of imbibition (water absorption) 
     5Radicle emerged 
     7Coleoptile emerged 
     9Leaf just at coleoptile tip 
    1 Seeding development1
     0First leaf through coleoptile 
     1First leaf at least 50% emerged 
     2Second leaf at least 50% emerged 
     3Third leaf at least 50% emerged 
     4Fourth leaf at least 50% emerged 
     5Fifth leaf at least 50% emerged 
    2 Tillering2
     0Main shoot only 
     1Main shoot plus 1 tiller visible 
     2Main shoot plus 2 tillers 
     3Main shoot plus 3 tillers 
     4Main shoot plus 4 tillers 
     5Main shoot plus 5 tillers3
    3 Stem elongation 
     1First node detectable6
     2Second node detectable7
     3Third node detectable 
     7Flag leaf just visible8
     9Flag leaf collar just visible9
    4 Boot 
     1Flag leaf sheath extending 
     3Boot just beginning to swell 
     5Boot swollen10
     7Flag leaf sheath opening 
     9First awns visible 
    5 Head emergence 
     1First spikelet of head just visible10.1
     3One-fourth of head emerged10.2
     5One-half of head emerged10.3
     7Three-fourths of head emerged10.4
     9Head emergence complete10.5
    6 Flowering (not readily visible in barley) 
     1Beginning of flowering10.5.1
     5Half of florets have flowered10.5.2
     9Flowering complete 
    7 Milk development in kernel 
     1Kernel watery ripe10.5.4
     3Early milk 
     5Medium milk11.1
     7Late milk 
    8 Dough development in kernel 
     3Early dough 
     5Soft dough11.2
     7Hard dough, head losing green color 
     9Approximate physiological maturity 
    9 Ripening 
     1Kernel hard (difficult to
    divide with thumbnail)
    11.3
     2Kernel cannot be dented by
    thumbnail, harvest ripe

    Source. http://www.extension.umn.edu/agriculture/small-grains/growth-and-development/spring-wheat/wheat growth stages

    About Muhammad Ramzan Rafique

    I am from a small town Chichawatni, Sahiwal, Punjab , Pakistan, studied from University of Agriculture Faisalabad, on my mission to explore world I am in Denmark these days..

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