The study of heterosis over environment in bread wheat, Triticum aestivum
THE STUDY OF
ENVIRONMENT IN BREAD
DEPTT:- Plant Breeding & Genetics
University Of Agriculture, Peshawar
INTRODUCTION TO BREAD
• Bread wheat is more widely cultivated than any other crop.
Bread wheat is one of the world’s three main cereal crops, along
with rice and maize.
• Triticum aestivum, common or bread wheat, is an annual grass, native
to the Mediterranean region and southwest Asia, which is one of
several species of cultivated wheat.
• A significant portion of it is used for livestock feed and biofuel, rather
than human food.
• Wheat is one of the most ancient of domesticated crops, with
archaeological evidence of the cultivation of various species in the
Fertile Crescent dating back to 9,600 B.C.
• The various species have been developed into thousands of cultivars
(over 25,000, by one estimate).
• Cultivars are categorized according to
1. horticultural requirements (spring vs. winter wheat),
2. texture and food uses (hard wheat, which often contains more gluten
and is used for bread; vs. pastry or flour wheat, used for cakes,
biscuits, and cookies),
3. or by growth form and
4. seed characteristics (the varieties aestivum, compactum,
and spelta are among the six major categories recognized).
• Wheat is high in carbohydrates, protein and vitamins B and E and is
used in countless breads and baked goods, and is an important source
of calories for over 1 billion people in the world.
• Wheat can be refined into starch and wheatgerm oil, and wheat gluten
(the proteins that make it sticky) is used in many products.
• Wheat is also used to make beer and as animal fodder.
• The wheat hybrid is produced by crossing two pure lines.
• The hybrid is seen to have a higher agronomic value than its parents.
• The term used to describe this is hybrid vigour or heterosis.
• This trait is expressed in the yield potential and yield consistency and
the grain quality.
• The hybrid wheat thus show heterosis, heterobeltiosis, in different
environments, and therefore heighlights economic, agronomic,
technological and environmental advantages.
• The hybrid wheat varieties are more productive than conventional
wheat due to the hybrid vigour (heterosis).
• Some hybrid wheats can increase the yield by more than 15%, when
compared to average of their parents, and even more in stressful
Heterosis over environment:-
• When we cross two pure lines, we get F1 Hybrid.
• In hybrids we study heterosis.
• Utilization of heterosis through hybrid wheat is more attractive than
conventional plant breeding methods, which obtain lower yield gain.
• NOW; The study of heterosis over environment has a direct bearing on
the breeding methodology to be employed for varietal improvement.
• Studies of heterosis also provide useful information about combining
ability of the parents and their usefulness in breeding programs.
• Estimation of heterosis over the better parent (heterobeltiosis) may be
useful in identifying true heterotic cross combinations.
• Wheat breeders dealing with various aspects of hybrid wheat found
that the standard heterosis for grain yield, on a large plot basis, ranged
from 6% (BORGHI et al. 1986) to as high as 41% (ZEHR et al. 1997).
THE EFFECT OF HETEROSIS APPARENT IN
• Grain productivity higher than the parental lines.
• Outstanding tillering ability.
• A more developed root system that penetrates more extensively into
soil compared with self-pollinating varieties.
• Greater tolerance to stress (cold, excess water, drought), thereby
contributing to more regular yields from one year to next.
• The combination of parental genes and plant’s growth habitat make
hybrid wheats behave in a very interusting fashion, faced with certain
• The present literature revealed that a satisfactory bread making
properties combined with high yields can be obtained with at least first
generation of hybrids.
• Parental lines having superior quality parameters when combined with
genetically diverse high yielding superior ideotype may result in
hybrid combinations which may be superior in economic yield or
quality over the best check.
• Enough experience has been gained to start this project.
• The project will be used to invite the B.Sc students to
visit, and get the basic information.
• The project will be used to train M.Sc students.
• The project will be used as a part of the Ph.D dissertation
for training a Ph.D scholar.
• To get significant positive heterobeltiosis for grain yield per plant in
• To Increase thousand grain weight.
• To improve tolerance to disease.
• To determine high quality protein varieties.
• To Stabilize technological baking quality.
• Selection of parents.
• Crosses will be made in all possible combinations in a randomized
block design with three replications under early (E1- 1st November),
normal (E2- 20th November) and late (E3- 10th December) sown
• 40-70% of the hybrids retained by crossing will be assessed to see the
mid parent heterosis, or heterobeltiosis (best parent heterosis) in the
above given three environmental conditions
• The varieties retained will undergo further trials in the second years
with wider systems in the large wheat-producing areas throughout
• During this time, every hybrid will be scored regularly in order to
characterize its health profile.
• Bread making trials will be also carried out to identify clearly the
technological quality offered by each variety.
• The hybrids and their parents will undergo official trials. The high
yielding hybrids will be listed officially and will become marketable.
• Statistical analysis of the data, completion of results, drawing of
conclusions and recommendations and suggestion for further research
will be done.
• Writing of final report.
• In our developing society most of the people are not capable to afford
the high rates, so the hybrids produced will be of low rates and will
also provide balanced diet, sufficiently rich in protein.
• It will be an initiative step to make our country self sufficient in wheat
• Scientific personnel required for the project:
One Research Officer Full Time
• Existing institutional facilities:
Offices and library equipped with recent
books and journals.
• Scheme has been submitted to some other aid giving agency:
Year Recurring Non-recurring Total
1st Year 596000 - 596000
2nd Year 596000 - 596000
3rd Year 596000 - 596000
Grand Total 1788000 - 1788000
Post & Pay Scale No. of Posts 1st year 2nd year 3rd year Total
Research Officer @ Rs
Field Assistant @ Rs.
Co- Principal Investigator
(Ii)Travel Within Province
(For Project Involving
Field Work Only)
S. No. Item 1st 2nd 3rd Total
Consumable Store (Fertilizer,
insecticides bags, tags, etc.)
Daily paid labor
Total 66000 66000 66000 198000
Expenditure on Equipment & Supplies
• LITERATURE CITED:-
• Borghi B., Corbellini M., Cattaneo M. M. et al., (1986). Modification
of the sink/source relationships in bread wheat and its influence on
grain yield and grain protein. J. Agron. Crop Sci. 157: 245–254.
• Borghi B., Perenzin M. and Nash R. J., (1988). Agronomic and
qualitative characteristics of ten bread wheat hybrids produced a
chemical hybridizing agent. Euphytica. 39: 185–194
• Darrell G. W. and Charles L. L., (1970). Hybrid vigour in hard red
spring wheat crosses. Crop Sci. 10: 220–223.