Soft and hard grain mutants induced in common wheat variety K68

Devender KUMAR

Department of Agricultural Chemistry, R.B.S. College, Bichpuri, Agra 283105, U.P. India

Introduction

Concept of grain quality in wheat depends on the intended use and the consumers' preference. Hard wheats with strong gluten (AUSTIN and RAM 1971), a good balance of dough properties (SWANSON and JOHNSON 1943 and ABROL et al. 1972) and generally rich in protein are chiefly consumed for bread-making purposes. Soft wheats, on the other hand, with weak gluten and low in protein are consumed for biscuit and cake preparations. Thus, in view to meet the specific demands, it is imperative to develop soft and hard grain wheat varieties.

Protein content and the gluten strength are the chief components of baking quality. Besides, the attributes, viz., dough mixing, dough stability, mixing time etc. are also to be considered for this purpose. National-Swanson-Working-Dough-Mixer has widely been used to measure these properties (MEHDI et al. 1971 and ABROL et al. 1972). The present study was, therefore, initiated to classify thirteen homozygous mutants in soft and hard groups on the basis of their mixogram properties, total protein and gluten strength.

Material and Methods

Thirteen homozygous mutants were obstained from ⁶⁰Co gamma-ray treated seeds of common wheat variety K68. These mutants along with control were assessed for total protein and pelshenke value (gluten strength) in usual manner in M₄ generation. Mixogram characteristics were recorded from mixographs drawn by National-Swanson-Dough-Mixer in Cumming's Laboratory, IARI, New Delhi. Thirty gm of fine flour was used. Twenty one ml of water was added into mixing bowl and spring tension was set at 10. Measurements were recorded from the graphs according by SWANSON and JOHNSON (1943) and JOHNSON et al. (1943) as follow :

(1) Mixing time for dough development to maximum consistency (min).

(2) Height of the curve (cm)

(3) Rate of dough development (degrees)

(4) Rate of dough weakening (degrees)

(5) Dough development area (cm²).

Results and Discussion

Data on mixogram characteristics total protein and pelshenke value of mutants and control are presented in Table 1. The mutants HUW-SDf9, SDfl7 and SStd8 were characterized as soft wheats. Which is evident from low pelshenke value (60 min), low mixing time (1.5 min), low dough development area and quite high angle of weakening (8 degrees). WELSH and NORMAN (1972) have also reported that soft wheats possessed weak gluten and short mixing time. Such flour gives poor dough which tends to run out when fermentation proceeds and consequently may produce heavy loaves of unsatisfactory texture. Flour of these mutants is thus principally suited to biscuit and cake preparations.

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