Heterosis and Gene Effect Studies for Seed Yield and Related Traits in Indian-Mustard (Brassica juncea L. Czern & Coss) Thesis Submitted to G. B. Pant University of Agriculture & Technology, Pantnagar- 263145, U.S. Nagar, Uttarakhand, India By Sanjana Pathak B.Sc. IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE DEGREE Of Master of Science in Agriculture (Genetics and Plant Breeding) July 2016 ACKNOWLEDGEMENT Every project big or small cannot be successful without the efforts of people who genuinely offer help and support to the best of their capability and knowledge. I take this opportunity to thank all the wonderful people whose efforts are visible on every single page of this thesis. At this juncture, I feel deeply honored to extend gratitude to my advisor Dr. Usha Pant, J.R.O., Department of Genetics and Plant Breeding who has been a friend, philosopher and a wonderful guide throughout my degree programme. I want to thank her for making the resources available at the right time, for inspiring me when I was not feeling confident, for offering honest criticism wherever it could improve my work and spending long hours in the field and the laboratory just to make sure that my work kept moving at a smooth pace. Her benevolence, sincerity and hard work will always keep her alive in my memories as the best guide I could have had during the course of my programme. This thesis would have not turned out the way it has without the experience, intellect and empowering acumen of Dr. Ram Bhajan, Professor, Department of Genetics and Plant Breeding, who patiently answered my queries, offered his vast expanse of knowledge and made sure that every detail of thesis was free from mistakes and flaws. A debt of gratitude is owed to Dean, College of Agriculture; Dean, College of Post Graduate Studies; Registrar; Head, Genetics & Plant Breeding and University librarian for providing me the essential facilities to conduct the proposed investigations. Kind cooperation extended by all the members of the oilseed breeding. I am grateful to Joint Director, Norman E. Borlaug Crop Research Centre, Pantnagar and Director, Experiment stations for providing me the essential facilities to conduct the proposed investigation. The knowledge and expertise used for this thesis was made accessible to me by the members of my advising committee especially Dr. Anil Kumar, J.R.O, Department of Genetics and Plant Breeding and all the respected teachers of our department. I extend my deepest regards to Mr. Dinesh Singh Karki, Mr. Thapa, Mr. Ramdhyan and all the workers of oilseed breeding group who supported my work in every possible way both in the laboratory and field. I wish to acknowledge my family for the never ending affection, blessings and for having faith in my potential. I am immensely pleased to offer every single synonym of gratitude to my father Late Mr. Sanjay Pathak whose conviction and lessons have never left me alone even in the hardest of times. The kindness of my mother Mrs. Krishna Pathak and inspiring devotion of my brother Mr. Devesh Pathak gave me the courage to take the right decisions when the tide was not in my favor. There are no words in the dictionary that can correctly fathom the tremendous energy and love that has been showered upon me by my dearest friends Laxmi Pangti, Tabassum Ahmed, Seema Prasad, Aolemla Pongen, Vineha Puri, Shikhar Sharma, Chetna Kandpal, Ajay Kumar Dhyani, Lalit Joshi and my senior Deepankar Pandey. These people offered laughter, empathy and encouragement that kept me cheerful throughout my journey. Pantnagar July, 2016 CERTIFICATE This is to certify that the thesis entitled “Heterosis and Gene Effect Studies for Seed Yield and Related Traits in Indian-Mustard (Brassica juncea L. Czern & Coss)” submitted in partial fulfilment of the requirements for the degree of Master of Science in Agriculture with major in Genetics and Plant Breeding of the College of Post Graduate Studies, G.B. Pant University of Agriculture and Technology, Pantnagar, is a record of bona fide research carried out by Ms. Sanjana Pathak, Id. No. 45470, under my supervision and no part of the thesis have been submitted for any other degree or diploma. The assistance and help received during the course of this investigation have been acknowledged. CERTIFICATE We, the undersigned, members of the Advisory Committee of Ms. Sanjana Pathak, Id. No. 45470, a candidate for the degree of Master of Science in Agriculture with major in Genetics and Plant Breeding agree that the thesis entitled “Heterosis and Gene Effect Studies for Seed Yield and Related Traits in Indian-Mustard (Brassica juncea L. Czern & Coss)” may be submitted in partial fulfilment of the requirements for the degree. CONTENTS S. No. CHAPTER PAGE No. 1. INTRODUCTION 2. REVIEW OF LITERATURE 3. MATERIALS AND METHODS 4. RESULTS AND DISCUSSION 5. SUMMARY AND CONCLUSIONS LITERATURE CITED VITA ABSTRACTS LIST OF TABLES Table Title No. 3.1 Weather data and weather report at Pantnagar during 2015-16. 3.2 Description of Family A 3.3 Description of Family B 3.4 Description of Family C 3.5 Description of Family D 3.6 Number of plants selected randomly for study in each generation 3.7 Analysis of variance for pooled analysis 3.8 Genetic models and their parameters 3.9 Chi-square test for goodness of fit for different models in the order of increasing complexity 3.10 Generation mean, weights and coefficients 4.1.1 Pooled analysis of variance (Compact Family Block Design) of different families for various quantitative characters 4.1.2 Pooled analysis of variance (Compact Family Block Design) of different families for various quantitative characters 4.2.1.1 The estimates of scaling tests for days to maturity 4.2.1.2 The estimates of scaling tests for plant height 4.2.1.3 The estimates of scaling tests for length of main raceme 4.2.1.4 The estimates of scaling tests for number of primary branches per plant 4.2.1.5 The estimates of scaling tests for number of secondary branches per plant 4.2.1.6 The estimates of scaling tests for number of siliquae on main raceme 4.2.1.7 The estimates of scaling tests for number of siliquae length 4.2.1.8 The estimates of scaling tests for number of seeds per siliqua 4.2.1.9 The estimates of scaling tests for 1000-seed weight 4.2.1.10 The estimates of scaling tests for oil content 4.2.1.11 The estimates of scaling tests for seed yield per plant 4.2.1.12 The estimates of scaling tests for glucosinolate content 4.2.2.1 Adequacy of different models by test for different characters for Family A 4.2.2.2 Adequacy of different models by test for different characters for Family B 4.2.2.3 Adequacy of different models by test for different characters for Family C 4.2.2.4 Adequacy of different models by test for different characters for Family D 4.2.3.1 Estimates of genetic parameter under the adequate genetic model with respective value and type of epistasis involved for days to maturity 4.2.3.2 Estimates of genetic parameter under the adequate genetic model with respective value and type of epistasis involved for plant height 4.2.3.3 Estimates of genetic parameter under the adequate genetic model with respective value and type of epistasis involved for length of main raceme 4.2.3.4 Estimates of genetic parameter under the adequate genetic model with respective value and type of epistasis involved for number of primary branches per plant Table Title No. 4.2.3.5 Estimates of genetic parameter under the adequate genetic model with respective value and type of epistasis involved for number of secondary branches per plant 4.2.3.6 Estimates of genetic parameter under the adequate genetic model with respective value and type of epistasis involved for siliquae on main raceme 4.2.3.7 Estimates of genetic parameter under the adequate genetic model with respective value and type of epistasis involved for number of siliqua length 4.2.3.8 Estimates of genetic parameter under the adequate genetic model with respective value and type of epistasis involved for number of seeds per siliqua 4.2.3.9 Estimates of genetic parameter under the adequate genetic model with respective value and type of epistasis involved for number of 1000-seed weight 4.2.3.10 Estimates of genetic parameter under the adequate genetic model with respective value and type of epistasis involved for oil content 4.2.3.11 Estimates of genetic parameter under the adequate genetic model with respective value and type of epistasis involved for seed yield per plant 4.2.3.12 Estimates of genetic parameter under the adequate genetic model with respective value and type of epistasis involved for glucosinolate content 4.3.1 Gene effects vis-à-vis observed heterosis over MP and estimated heterosis based on gene effects for seed yield 4.3.2 Gene effects vis-à-vis observed heterosis over MP and estimated heterosis based on gene effects for number of primary branches per plant 4.3.3 Gene effects vis-à-vis observed heterosis over MP and estimated heterosis based on number of secondary branches per plant 5.1 Adequacy of genetic models by 2 test for different characters IInnttrroodduuccttiioonn C h a p t e r - 1 INTRODUCTION Oilseed brassicas, also known as rapeseed-mustard, are among the largest traded agriculture commodities. The combined volume of exports of rapeseed and mustard seed oils is almost 10.07% of the total vegetable oilseeds. Growing importance and consequent research investments have led to dynamic breakthroughs in yield and seed quality. Modification of the seed oil and reduction of meal glucosinolate content by Canadian breeders in rapeseed during the early 1970’s was a plant breeding feat that stands next only in importance to the agricultural modification in cereals. Since then, enormous strides have been made. Hybrids have been commercialized, and all crop brassica genomes were sequenced. World output of rapeseed mustard crops rose from about 36 million tons in 2001/2 to 70 million tons in 2013/14. However the demand for rapeseed-mustard oils continues to escalate steeply due to increasing consumption and diversion of bioenergy use. Rapeseed-mustard crops in India include toria (B. rapa L. var. toria), brown sarson (B. rapa L. var. brown sarson), yellow sarson (B. rapa L. var. yellow sarson), Indian mustard [B. juncea (L.) Czern & Coss], black mustard (B. nigra) and taramira (Eruca satva / vesicara Mill.) species. These along with non-traditional species like gobhi sarson (B. napus L.) and karan rai (B. carinata A. Braun) have been recorded to be grown since ancient time. Indian mustard occupies more than 80% of the total rapeseed mustard cultivated area, contributes nearly 27% of edible oil pool in India, and accounts for >13% of the global edible oil production. It ranks second after groundnut in oilseed crops. Extracted oil of mustard is used for cooking media as well as industrial purposes. The seeds are used as spices in the preparation of pickles, curries, sauces and salad. Mustard tender leaves are also used for culinary purposes. The meal cake is used as cattle feed and seeds have medicinal properties. In Northern India, mustard oil is mainly utilized for human consumption (Vaghela et al., 2011). During the last decade, the yield of mustard in India is almost static, hovering around 1-1.2 tonnes/ha, which is much below than the world’s average of 1.98 tonnes/ha. There is a much wider yield gaps when productivity of mustard in India is compared with 4.3 tonnes/ha in Germany, 3.8 tonnes/ha in France and 3.4 tonnes/ ha in UK (Yadava et al., 2012). Indian mustard (Brassica juncea, AABB; 2n = 36) is a natural amphiploid between B. rapa (AA; 2n = 20) and B. nigra (BB; 2n = 16). It arose several times through independent hybridization events in the sympatric areas of the diploid progenitor species (Prakash et al., 2009; Kaur et al., 2014). Its genetic base, restricted by the dual bottlenecks of polyploidy and domestication, stands further eroded by intensive plant breeding activities (Chauhan et al., 2011; Banuelos et al., 2013). Narrow genetic base coupled with a lack of architectural variations is now undermining the ability of plant breeders to improve productivity in this premier oilseed crop of Indian sub-continent. B. juncea also possesses adaptive potential for drier ecologies of Australia and Canada (Wijesundera et al. 2008). Like other alloploid crops, Indian mustard expresses low heterosis (Bansal et al. 2012). As allelic diversity is considered central to the expression of heterosis (Falconer and Mac-Kay 1996), intensive efforts have been made to widen its genetic base by exploiting various germplasm sources (Banga and Labana 1984; Jain et al. 1994) or by artificial resynthesis (Bansal et al. 2009, 2012). Due to its wide cultivation it is essential to identify high yielding genotypes on the basis of genetic parameters to formulate effective breeding programme. The important economic character which is of prime importance is yield and is an outcome of multiplicative interaction of component characters. For breeding high yielding varieties of crop plants, breeders usually face the problem of selection of desirable parents. In general, parents are selected on basis of their per se performance, but many times high yielding genotype may/may not transmit its superiority to progeny. Knowledge of genetic parameters is vital for the effectiveness of selection for improvement of target character. Interrelationship among characters is highly useful in selecting characters, which are not easily observed or genotypic values of which are modified by the environmental effects. It also helps the breeders to know the nature, extent and direction of selection pressure among the characters. However, information on such aspects involving physiological parameters of Indian mustard is lacking. Large genotype × environment effects tend to be viewed as problematic in breeding because the lack of a predictable response hinders progress from selection (Dudley and Moll, 1969). Dudley (1997) have emphasized that information on the inheritance of quantitative traits have application in planning breeding strategies for cultivar development. Finding a suitable breeding method and identifying a selection strategy for trait improvement would depend on the knowledge of gene effects operating in the breeding population.