Developing of dual (fodder/grain) sorghum genotypes

Developing of dual (fodder/grain) sorghum genotypes

(in collaboration with Suad A. Hassan)

Suaad .Hassan and Maarouf I. Mohammed

Being a possible centre of origin, Sudan is endowed with a wealth of genetic variability in sorghum enabling selection for most economic traits. Efforts to exploit such variability to develop dual sorghum types have been very limited and mostly directed towards developing improved grain types. Simultaneous improvement of sorghum for both fodder and grain attributes will help in meeting the demand for feed and food and allow maximum utilization of the available variability. The ultimate objectives of this project were to develop dual purpose (fodder/grain) sorghum genotypes having the potential of combining, to the maximum possible, improved feed and food attributes.
A breeding nursery comprising 122 sorghum genotypes of different grain, grass and sweet sorghum types was established in 2010.

Fig. 1. The breeding nursery (2010, Shambat)

Twenty one genotypes were selected based on high dual grain/forage yield and related attributes with more emphasis given to earliness, regrowth and leaf to stem ratio. In 2011, the 21 selected genotypes plus 3 standard checks were evaluated for dual forage/grain attributes. Six genotypes selected for their high dual purpose performance (Table 1) were tested against the check Abnaffain, a traditional dual grain/forage cultivar. The performance of the 7 genotypes was assessed during summer and winter seasons (2012-2012/2013) under two harvest options viz:

· Option1: The crop was cut at heading time to evaluate forage production and the ratoon (regenerated crop) was left to grow up to maturity stage to evaluate grain production
· Option2: The crop was left to grow up to grain maturity to evaluate grain and stover yield.

Table 1. The selected dual (fodder/grain) sorghum genotypes
Genotype	Population	Initial usage	Grain color	Mid-rib color
S.25Abu70	Abu Sabein	Forage	White	Green
S.03Abu70	Abu Sabein	Forage	White	Green
Abjaro	Abjaro	Grain	White	White
SG08	Sudan grass	Forage	White	Green
SG51	Sudan grass	Forage	White	Green
E-35-1	Sweet sorghum	Forage	White	Green
Abnaffain	Dual check	Grain/forage	White	White /Green

Fig.2. Evaluation of 21 sorghum genotypes selected for dual fodder/grain attributes (2011, Shambat)

Fig.3. Evaluation of 21 sorghum genotypes selected for dual fodder/grain attributes (2011, Shambat)

Fig.4. Assessing the performance of six dual fodder/grain selections against the traditional dual check Abnaffain was (Shambat, 2012-2012/2013)

When harvesting the main crop for forage and grain from ratoon crop, Abjaro seemed to give the best forage yield and ratoon grain yield specially during winter season. Its GMY and DMY averaged 47.9 and 10.9 t/ha, respectively. S.25Abu70 ranked second with respective yields of 43.8t/ha and 8.29 t/ha. The winter ratoon grain yield of Abjaro was strikingly high (1504 kg/ha) exceeding that of S.03Abu70 (the 2^nd best genotype) by > than twice and that of Abnaffain by > 3 folds. The genotypes S.03Abu70 in winter and S.25Abu70 in summer ranked second to Abjaro in grain yield. In spite of that the choice of farmers may go for Abu Sabein since it was remarkably earlier than Abjaro specially in the summer season. This is specially true for S.25Abu70 in summer season which was 58 day earlier in heading time while keeping comparable ratoon grain yield to Abjaro. The benefits gained from increased forage yield of Abjaro over that of Abu Sabein may not justify affording additional costs and implications imposed by delaying harvest for nearly 2 months. On the other hand, S.25Abu70 may represent a good replacement for Abnaffain when used for producing forage and grain from main and ratoon crop, respectively.

When harvesting grain and stover from the main crop, Abjaro also kept the top rank in both attributes in winter and summer seasons with respective grain yields amounting to 4139 t/ha and 3086 t/ha, whereas the respective stover yields were 58.6 t/ha and 39.8t/ha. However, Abjaro yields were not significantly different from that of Abu Sabin genotypes except for stover in the summer season. Considering the lateness of Abjaro, farmers may favor growing Abu Sabin for grain / stover production in both seasons unless the stover value of the summer season is high enough to justify growing Abjaro, or if quality aspects of the stover were considered. In the Sudan, sorghum stover has the greater contribution in maintaining the national herd. High stover yielding cultivars are becoming increasingly valued over high grain-low stover yielding ones. In this study, the quality of stover was not investigated, however, the data presented for leaf to stem ration showed that Abjaro was leafier than Abu Sabein genotypes.

Fig. 5 Late maturing Abjaro (in the middle

It could be concluded that the performance of dual sorghum cultivars differ across harvest options and seasons. To maximize grain and fodder yields from dual sorghum cultivars, different genotypes were suggested for different harvest options in different seasons. When harvesting the main crop for forage and grain from ratoon crop, the best choice is to grow the cultivar Abjaro during winter and S.25Abu70 during summer. When harvesting grain and stover from the main crop, Abjaro also kept the top rank in both attributes in winter and summer seasons however, considering the lateness of Abjaro, farmers may favor growing Abu Sabein unless the stover value of the summer season is high enough to justify growing Abjaro, or if quality aspects of the stover were considered. Future results should focus on developing dual sorghum cultivars with high quality stover with special emphasis on improved digestibility.

More details could be found in the following link:

http://www.academicjournals.org/journal/JPBCS/edition/April_2015

Aklamoi nursery

'Aklamoi', is the predominant traditional sorghum type in Kassala district, favored for its excellent grain quality and juicy sweet stems. It is traditionally cultivated as both fodder and grain crop under residual moisture of Gash delta. It is a landrace with great genetic variability. Selection among such population may result in breeding materials enhanced for dual or multipurpose breeding attributes.

Twenty Aklamoi accessions received from Plant Genetic Resources Unit, Agricultural Research Corporation, Wad Medani were grown in a replicated breeding nursery in the summer of 2013. Great variability was observed among and between accessions for plant height, stem thickness, leafiness, Juiciness (Mid-rib color), flowering duration, head and grain characteristics etc… Selection was practiced for characters contributing to simultaneous maximization of grain, fodder and stem-juice yield. Seeds from the selected plants were grown in 2013/2014. Three individual plant selections were made (Aklamoi short, Aklamoi tall and Aklami yellow)

Fig. 6. Yellow (Brown) mid-rib of aklamoi

Hybridization and selection among local sorghums for dual purpose attributes


Fig. 7. Preparing panicle for crossing

Using plants growing in the advanced yield trial conducted during the winter season 2012/013, the traditional cultivar Abjaro was crossed as female parent with the following pollen sources: SG51, S03Ab70, S25Ab70 and Abnafain. The objectives were to bring together the desired traits of Abjaro (i.e. high stover and grain yields) with that of male parents (i. e. juiciness and earliness). The crossings were made on the last week of Feb and the first week of March 2013 using plastic bag technique.

Fig.8. Plastic bag technique

The F1 seeds were grown in a breeding nursery in 14 May 2013 together with parental seeds. The F1 plants were determined and F2 seeds were collected from crosses other than Abjaro x S25Ab70 and grown together with those of the parents in a breeding nursery established on 19/Dec. 2013. Selection was practiced for desired Abjaro traits plus juiciness (green mid-rip) and earliness. Presently (2016/017), the materials are in F6 and 8 promising lines are expected to be tested in a preliminary yield trial.

Similarly, crosses were made between Abnafain, SG51 and S03Ab70 (as females) with the 3 Aklamoi selections made during 2013/2014 (Aklamoi short, tall and yellow). The F2 plants of these crosses are now under evaluation.