What is Rouging? Rouging for quality seed production, A major source of off-type plant, Rouging in Certified Seed Production, Rouging During rice seed production.

1. 2017-18

2. Significance of Rouging
What is Rouging?
 Rouging: - The selective removal of undesirable plants from a seed crop on the basis
of visual field inspection, in order to improve one or more quality (genetic purity,
disease free) attributes of the seed lot to be harvested" (Laverack and Turner 1995).
 Removal of noxious weeds (wild oat in wheat, and Argemone mexicana in Brassica
species) that are liable to multiply with the seed crop, thus affecting future
generations, may be regarded as part of rouging.
 Rouging at all stages of the crop in the field is an essential requirement to maintain
the variety purity as it was at the time of release/notification.
 Sometimes rogue plants are not distinguishable before flowering, therefore, rouging
should be done, as early as blooming starts.
 Doubtful plants too should be rouged.
 The rogued plants should be removed from the field immediately after rouging and
destroyed as they may survive for a few days and may spread their pollen.
 Rouging for Quality Seed Production
Rouging is the removal of plants which are off-type that is phenotypically
different from the plants of the variety under production. It is an important aspect of
seed production and is necessary to prevent out-crossing and mechanical mixtures.
The off-type plants are to be regularly removed from the field either by uprooting
or by cutting at the ground level.
The off-type plants may differ in –
 Plant height: Taller or shorter than most of
the plant.
 Plant characters: Presence or absence of
awn etc.
 Leaf characters: Different leaf colour, different angle of flag leaf, erect or droopy leaf
type etc.
 Flowering time: Early or late flowering or panicle initiation.

3.  Maturity: Different time.
 Panicle: Rogue plants with partially exerted panicles because at heading time, these
off-types will have earlier or later panicle emergence.
 Flag leaf angle: Rogue plants with flag leaf that is upright (A) or bent (B) unlike the rest
of the plants.
 Leaf color, sheath, stem: Rogue plants that have discoloured or differently- coloured
leaves, sheath, stems.
Besides off-type plants, diseased plants, weeds above or below canopy, lodged or
disabled plants, mechanically damaged plants etc. should also be removed or rouged out
to obtain a clean seed production field. The upper view of a rouged plot should look fairly
plain and distinct.
Major Sources of Off- type Plant
There are three main sources of off- type
1) The off-type plant may be arising due to presence of recessive genes in heterozygous
condition at the time of release of variety. (The recessive genes may also arise by
mutation).
2) Off-type plants are due to volunteer plants or from seed produced by earlier crop.
3) Mechanical mixtures also constitute the major source foe off- type plants.
Rouging in Certified Seed Production
The most important object of the seed production is to maintain genetic purity of the
variety or hybrids seed plot. For this purposes it is necessary to follow rouging
vigorously.
Rouging consists of removal of
a) Off types
b) Volunteer plants
c) Pollen shedders in female (A) lines,
d) Plants of noxious weeds and other crops,
e) Diseased plants affected by seed borne diseases growing in the seed plot and

4. f) Tassels from plants in the female rows of seed production of single hybrids and
double hybrids in maize.
Rouging is to carried in three phases
a) Pre Flowering
b) During Flowering and
c) Post flowering or before harvesting.
During pre-flowering period plants which are morphologically distinguishable from true
characters of the variety should be removed. Similarly, volunteer plants, other crop
plants, weed plants should also be checked.
During flowering period which lasts for 15 to 30 days rouging should be carried more
critically and all off types, volunteer plants, and pollen shedders in MS lines should be
removed before shed pollens. Timely rouging during flowering helps in preventing natural
cross pollination and also reduces the proportion of off types. Simultaneously isolation
area on sides of seed plot be checked for removing volunteer plants before they flower.
Plants affected by seed borne diseases, other crop plants and tall growing weed plats
should also be removed. In case of seed plots of both single and double hybrids of maize
work of detasseling should be carried in female lines before they shed pollens.
Rouging should be continued during seed development stage and before harvesting for
removing visibly distinct off types other crop plants and diseased plants. Post flowering
rouging is admissible in seed production of self-pollinated crops.
Rouging during rice seed production
OBJECTIVE: To understand the importance of rouging to maintain genetic purity.
Rouging is the removal of all off-types or mixtures of plants. Rouging in any seed
production plot is extremely important to prevent pollen from off-type plants causing
irreparable damage to the crop through cross-pollination.
Plants with heterogeneous characters in a seed production plot are off-types. Sources of
off-types are:
 Volunteer plants from a previous crop
 Natural out-crossing, or mutation
 Minor genetic variation in the seed used

5.  Developmental variation, and
 Mechanical mixtures during postharvest of the seed creation.
Off-types can be identified by observing the characteristics of plants:
 Plants taller or shorter than most of the population
 Plants with different color leaves, sheaths or straw
 Presence or absence of awns: if the existence of awns in a plant is different from
the rest of the population, it is an off-type
 Plants with earlier or later panicle emergence are off-types: Only plants that flower
within 2-3 days should be kept
 Angle of the lag leaf: If erect flag leaves are dominant in a crop, then horizontal or
droopy leaves are off-types.
 Inconsistent size, shape or color of grains: If most of the panicles have long grains
then those with medium grains are off-types. If slender grains are dominant, then
blood grains are off types
 Diseased- or insect-damaged plants.
Timing: Rouging should be done continuously over the whole growing season whenever
off-types are noticed. A special emphasis is needed during the period from panicle
emergence to early seed development.
References
 General Principles of Seed Production Technology - https://www.slideshare.net/RoshanParihar2/general-
principles-of-seed-production-technology
 Joan Adela Woods. Seed & Variety Selection Key Check 1: Used high quality seeds of recommended variety
Part 1: Understanding the PalayCheck System http://slideplayer.com/slide/10181583/
 Genetic Purity during Seed Production | Principles of seed technology -
http://www.agriinfo.in/default.aspx?page=topic&superid=3&topicid=83
 Requirements of Certified Seed Production
http://www.agriinfo.in/default.aspx?page=topic&superid=3&topicid=2294
 Rouging during rice seed production -
http://www.knowledgebank.irri.org/qualityseedcourse/index.php/module-2-production-of-rice-seed-in-
irrigated-mainmenu-103/7-roguing-mainmenu-51